If the ChekhovsArmory in ''Literature/HarryPotter'' were an actual army, it would curbstomp everyone in a massive ZergRush, and possibly hand the victory to our heroes without even trying. Also, there may be unmarked spoilers. Please list examples by book:

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[[folder:Harry Potter and the Philosopher's/Sorcerer's Stone]]
* An owl flutters past the window of Four Privet Drive on the morning after the night of Voldemort's defeat. As owls are soon revealed to be messengers for the magical community, this seems to subtly hint at the presence of a witch or wizard living in Little Whinging. In ''[[Literature/HarryPotterAndTheOrderOfThePhoenix Order of the Phoenix]]'', it is revealed that [[spoiler:their neighbor, Mrs. Figg, is a squib.]]
* Dumbledore appears "so suddenly and quietly you'd have though he'd just popped up out of the ground" and later disappears in the same way. Magical teleportation receives a proper name, Apparition, in the next book, and becomes an important method of transportation later in the series.
* Dumbledore's nose is described as "crooked, looking as though it had been broken at least twice." We learn in ''[[Literature/HarryPotterAndTheDeathlyHallows Deathly Hallows]]'' that it was broken by [[spoiler:his brother Aberforth at the funeral of their sister Ariana.]]
* Dumbledore's "Put-Outer" becomes critical to the plot about halfway through ''Deathly Hallows''.
* Dumbledore offers [=McGonagall=] a sherbet lemon (lemon drop in the American text). This is used as the password for his office in ''Chamber of Secrets''.
* Dumbledore mentions Madam Pomfrey complimenting his earmuffs. She appears later in the book as the school nurse.
* [=McGonagall=] mentions Godric's Hollow, which becomes a major location in ''Deathly Hallows'', [[spoiler:where we learn that it was named after Godric Gryffindor and that the Dumbledore family lived there for a time, also where Bathilda Bagshot lived. It will become crucial as Voldemort knows where to look]].
* The circumstances behind Harry's survival and Voldemort's initial destruction are discussed, but they are not revealed until ''[[Literature/HarryPotterAndTheHalfBloodPrince Half-Blood Prince]]'' and ''Deathly Hallows''. Dumbledore remarks that "we can only guess," though ''Half-Blood Prince'' reveals that he, in fact, began extensive research on the subject.
* Hagrid mentions borrowing the flying motorbike from Sirius Black. Sirius becomes a major character starting in ''[[Literature/HarryPotterAndThePrisonerOfAzkaban Prisoner of Azkaban]]'', while the bike itself reappears in ''Deathly Hallows''.
* Harry's scar initially seems to just be a scar. However, its importance increases significantly as the book and the series progresses.
* Harry is left on the Dursleys' doorstep with nothing but a blanket and a letter. The letter is not referenced again until ''Order of the Phoenix'' and ''Half-Blood Prince'', while the blanket comes back with a burning vengeance in ''Cursed Child''.
* Petunia Dursley is established as an important character, though a reader may wonder why Dumbledore took Harry to live with his horrible, abusive relatives or why Harry in the later books even bothers to return to the Dursleys' home at the end of each school year. In ''Order of the Phoenix'', it's revealed that [[spoiler:because she has Lily's blood in her, her presence protects Harry from Voldemort until he comes of age]].
* Mrs. Figg is a very minor character here and then does not appear again until ''Order of the Phoenix'', where she is important early in the plot.
* Harry discovers that he is able to communicate with a boa constrictor at the zoo. This ability, Parseltongue, is elaborated on in ''Chamber of Secrets'' and its origin in Harry is not explained until ''Deathly Hallows''.
* Harry remembers the flash of green light, which is not revealed to be the Killing Curse until ''[[Literature/HarryPotterAndTheGobletOfFire Goblet of Fire]]''. The fact that he has memories of when he was only one year old (and thus biologically unable to form memories) is indirectly explained in ''Deathly Hallows'' [[spoiler:as actually being the memories of Voldemort's Horcrux.]]
* Harry recalls being bowed to by a little man in a top hat, who is later revealed to be Dedalus Diggle. He does not become an important character until ''Order of the Phoenix''.
* Harry and the Dursleys stay at a hotel in Cokeworth. As revealed on ''Pottermore'', this is where Petunia and Lily [[spoiler:and Snape]] grew up, and the town reappears in ''Half-Blood Prince'' [[spoiler:when Bellatrix and Narcissa visit Snape at Spinner's End.]]
* Hagrid is repeatedly described as a "giant." In ''Goblet of Fire'', it is revealed that he is biologically half-Giant.
* Harry's letter lists "Order of Merlin, First Class" as one of Dumbledore's titles. It is revealed in ''Deathly Hallows'' that this was awarded to him in 1945 for defeating Gellert Grindelwald.
* Hagrid's dismissive attitude towards Muggles is a taste of anti-Muggle prejudice that is prominent later in the series.
* Vernon mentions having promised to "stamp out" Harry's magic. It seems like an idle threat at the time, but come the ''Fantastic Beasts'' movie, we learn that, not only is this possible, it's ''incredibly'' dangerous to all involved. It's very lucky for Harry, the Dursleys, and the world that he did not become an obscurial.
** Harry was unaware he was a wizard possessing magical ability, and therefore didn't know that he had something he could repress. This lack of knowledge is likely what saved him from becoming an obscurial, as it's implied most obscurials knew they were magicial and made a conscious choice not to use it.
* Hagrid mentions Voldemort's followers, who are not identified as Death Eaters until ''Goblet of Fire''. He also vaguely describes the First Wizarding War, which is elaborated on significantly in ''Order of the Phoenix''. Furthermore, Hagrid mentions the Bones and Prewett families, members of which later appear in the series (Molly Weasley and Susan Bones later in this book and Amelia Bones in ''Order of the Phoenix''), and the [=McKinnons=], all of whose deaths are elaborated on in ''Order of the Phoenix''.
* Hagrid speculates that Voldemort didn't have enough human left in him to die. ''Half-Blood Prince'' reveals that [[spoiler:no, he didn't.]] He also adds that some believe he's still out there "somewhere," which, in ''Chamber of Secrets'', is revealed to be Albania.
* Hagrid says that some of Voldemort's followers came out of trances, which is revealed to be caused by the Imperius Curse in ''Goblet of Fire''.
* Hagrid says that Hogwarts is "the finest school of witchcraft and wizardry in the world," implying that others exist. We learn about two others, Beauxbatons and Durmstrang, in ''Goblet of Fire'', and the others (Ilvermorny, Koldovstoretz, Castelobruxo, Uagadou, and Mahoutokoro) were later revealed on ''Pottermore''.
* Hagrid says that he was expelled from Hogwarts in his third year. The circumstances behind this are explored in ''Chamber of Secrets''.
* Hagrid explains how secure Gringotts is, that dragons guard the high security vaults, and also how unwise it is to try double-crossing Goblins. All of this comes up again in ''Deathly Hallows''.
* Hagrid says that Dumbledore declined to become Minister for Magic, but the actual reason is not revealed until ''Deathly Hallows''. He also mentions Cornelius Fudge, who appears in ''Chamber of Secrets'' and remains an important character until ''Half-Blood Prince''.
* Hagrid mentions that one reason for wizarding secrecy is that Muggles would want magical solutions to all of their problems. His answer was likely influenced by "The Wizard and the Hopping Pot," a fairy tale from ''Literature/TheTalesOfBeedleTheBard'' in which this is a major plot point.
* Harry's course books include ''A History of Magic'' by Bathilda Bagshot, who is important in ''Deathly Hallows'', and ''Fantastic Beasts and Where to Find Them'' by Newt Scamander, the protagonist of the five-movie prequel series. The latter text is also greatly expanded in the [[Literature/FantasticBeastsAndWhereToFindThem book of the same name]].
* Hagrid speculates on the reasons for Quirrell's twitchiness. Though the encounter that left him this way is later revealed to have been with [[spoiler:Voldemort]], the circumstances of this are not revealed until ''Goblet of Fire''.
* Hagrid and Harry pass Eeylops Owl Emporium, which includes snowy owls. One of these is Hedwig, who Hagrid buys for Harry later in the chapter.
* Griphook, the goblin who shows Harry to his vault, reappears in ''Deathly Hallows'' with an important role.
* Harry meets a boy at Madam Malkin's who is later revealed to be Draco Malfoy, a major character for the entire series. He mentions both of his parents, who also become important later in the series. His father, Lucius, first appears in ''Chamber of Secrets'', and his mother, Narcissa, makes her debut in ''Goblet of Fire''.
* Harry finds a book at Flourish and Blotts that mentions the tongue-tying curse, which comes up again in ''Deathly Hallows'' to [[spoiler:prevent Snape from revealing the location of 12 Grimmauld Place to the Death Eaters.]]
* Mr. Ollivander later becomes an important character in ''Deathly Hallows''.
* Ollivander mentions that James Potter's wand was "excellent for transfiguration." In ''Prisoner of Azkaban'', we learn that [[spoiler:he was highly skilled at transfiguration, as he was able to become an Animagus.]]
* The wand that chooses Harry has a phoenix feather core from the same phoenix that provided the feather for Voldemort's wand. Not only does the phoenix, Fawkes, appear in ''Chamber of Secrets'', but the matching cores is a critical plot point from ''Goblet of Fire'' on. [[spoiler: The fact that Voldemort and Harry were chosen by "brother wands" may also, like Harry's use of Parseltongue, be an early indication that the latter is an unknowing Horcrux of the former.]]
* Ron mentions his mother having a second cousin who is an accountant. The existence of squibs is revealed in ''Chamber of Secrets''.
* Ron mentions his father, Arthur, who becomes an important character from ''Chamber of Secrets'' on.
* Scabbers is merely Ron's pathetic pet rat. In ''Prisoner of Azkaban'', he becomes far more important when it is revealed that he is actually [[spoiler:Peter Pettigrew. FridgeHorror ensues]].
* The Trolley Witch makes her first appearance here and continues to be a minor character throughout the series until her full role and backstory are revealed in ''Cursed Child''.
* Dumbledore's Chocolate Frog card mentions both Gellert Grindelwald and Nicolas Flamel. The mention of Flamel is important later in the book, and Grindelwald is important in the backstory revealed in ''Deathly Hallows'' and is the villain of the prequel movies.
* Nott is one of the students who is sorted. He has an important role in the events leading up to ''Cursed Child''.
* Harry notices that Quirrell is wearing a purple turban that he was not wearing when they first met and shook hands. The reason for this turban is revealed at the end of the book.
* Blaise Zabini is sorted into Slytherin and then does not appear again until ''Half-Blood Prince'', where he has a minor role.
* Seamus asks Nearly-Headless Nick how the Bloody Baron got covered in blood. The answer is revealed in ''Deathly Hallows''.
* The feast vanishes and is replaced by dessert. It is revealed in ''Goblet of Fire'' that this is done by Hogwarts' staff of House-Elves.
* When Snape is introduced, he is looking directly at Harry. Not at his scar, but his eyes. The reason why is revealed in ''Deathly Hallows''. [[spoiler: (In the movie), you... you... have...Lily's eyes.....]]
* In the very same scene, Harry's scar begins hurting, but this is actually because Snape is explicitly looking past Quirrell's turban [[spoiler:under which Voldemort is sensing Harry.]]
* Percy explains that Snape knows a lot about the Dark Arts. We learn in ''Goblet of Fire'' that [[spoiler:he used to be a Death Eater.]]
* The Weasley twins are said to know more about the castle's secret passages than anyone. ''Prisoner of Azkaban'' reveals that this is because of [[spoiler:the Marauders Map.]]
* Professor Binns mentions Emeric the Evil and Uric the Oddball. They get a bit of expansion in ''Deathly Hallows'' and the ''Fantastic Beasts'' book, respectively.
* Quirrell's excuse for his turban is that it was a gift from an African prince for getting rid of a zombie. Inferi are important in ''Half-Blood Prince''.
* The bezoar mentioned briefly in Harry's first Potions class is later used in ''Half-Blood Prince'' for Harry to circumvent an antidote challenge, and [[spoiler: to save Ron after he accidentally drinks a bottle of poisoned mead.]]
* ''Quidditch Through the Ages'' is mentioned several times and is greatly expanded in the [[Literature/QuidditchThroughTheAges book of the same name]].
* The first years learn ''Wingardium Leviosa'', the levitation charm, which comes in handy later in the book as well as the series.
* Hermione's bluebell flames first appear with little importance but become very useful later in the chapter for [[spoiler:distracting Snape]] and later in the book for [[spoiler:repelling the Devil's Snare.]]
* When the students panic about the troll, Dumbledore shoots several fireworks out of his wand. In ''Deathly Hallows'', we learn that his wand is [[spoiler:the Elder Wand.]]
* The Snitch from Harry's first Quidditch match becomes important again towards the end of ''Deathly Hallows''.
* Ron's skill at wizard chess is established before Christmas and comes in handy later in the book.
* Two of Harry's Christmas presents are important later. Hagrid's flute is useful for [[spoiler:lulling Fluffy to sleep]] later in the book, while his father's invisibility cloak from [[spoiler:Dumbledore]] is important throughout the series and its true nature [[spoiler:as one of the Hallows]] is revealed in ''Deathly Hallows'', as well as the reason why [[spoiler:Dumbledore]] was interested in it.
* The Mirror of Erised is later used to [[spoiler:hide the Philosopher's Stone.]]
* On the way to the mirror, Harry and Ron pass "the ghost of a tall witch." This is the Grey Lady, A.K.A. [[spoiler:Helena Ravenclaw]], whose backstory is revealed in ''Deathly Hallows''.
* Dumbledore tells Harry that he can become invisible without using a cloak. He does so with a Disillusionment Charm, which first appears in ''Order of the Phoenix''.
* When Harry asks Dumbledore what he sees in the Mirror of Erised, he says a pair of woolen socks. What he actually sees, [[spoiler:his family alive and well]], is not revealed until ''Deathly Hallows''.
* The Elixir of Life produced by the Philosopher's Stone makes the drinker immortal. This hints at Voldemort's fear of death, which is revealed in ''Half-Blood Prince''.
* The first years learn about treating werewolf bites in Defense Against the Dark Arts. Come ''Prisoner of Azkaban'', [[spoiler:the teacher of that class ''is'' a werewolf.]]
* At one point, Harry has the horrible feeling that Snape could read minds." We learn in ''Order of the Phoenix'' that such an ability is known as Legilimency, though Snape is adamant that it is more complicated than simply reading minds.
* For a Quidditch victory party, Fred and George steal cakes from the kitchens. ''Goblet of Fire'' reveals that they're actually quite friendly with the House-elves.
* Harry looks up Dittany while studying. This plant reappears in ''Half-Blood Prince'' and ''Deathly Hallows'' for treating severe injuries.
* Hagrid says he won a dragon egg off a stranger in the village. The stranger turns out to be [[spoiler:Quirrell]] while the village, Hogsmeade, becomes an important location starting in ''Prisoner of Azkaban''.
* Filch says that he keeps chains in his office in case he's ever allowed to use them again. He almost gets the chance in ''Order of the Phoenix'', though [[spoiler:Umbridge is sacked before she can pass Educational Decree 29.]]
* Malfoy claims there are werewolves in the Forbidden Forest. When the nature of werewolves is explained in ''Prisoner of Azkaban'', his claim is revealed as anti-werewolf prejudice which is a part of the series from that book on.
* The centaurs reappear in ''Order of the Phoenix'' are important to the plot.
* Both Ronan and Bane say that "Mars is bright tonight." In ''Order of the Phoenix'', Firenze calls Mars the "bringer of battle." Their divination predicts that war is coming, and it eventually does. [[spoiler: Harry grouses that Bane probably wanted to let Voldemort kill him in the Forbidden Forest because the stars foretold such a thing. In ''Deathly Hallows'', Voldemort '''does''' kill Harry there, although it doesn't stick.]]
* [[spoiler:Quirrell]] drinks unicorn blood to make Voldemort stronger. Unicorn blood is later used in ''Goblet of Fire'' as one of the ingredients to [[spoiler:give Voldemort a body.]] Firenze also says that drinking unicorn blood curses the drinker, which seems accurate given that the rest of [[spoiler:Quirrell's]] life is unpleasant and short.
* Hermione says [=McGonagall=] told her that fortune-telling is "a very imprecise branch of magic." This is greatly expanded on in ''Prisoner of Azkaban'', with Professor Trelawney's Divination class.
* The trio goes to find Dumbledore only to realize they have no idea where his office is. The headmaster's office first appears in the next book.
* [=McGonagall=] says that Dumbledore flew to the Ministry of Magic. In ''Order of the Phoenix'' it is revealed that he rides one of the school's Thestrals when he doesn't feel like Apparating.
* Harry says that if Voldemort takes over, he would turn Hogwarts into a school for the Dark Arts. [[spoiler:This is exactly what he tries to do in ''Deathly Hallows'' and succeeds in doing in the bad timeline in ''Cursed Child''.]]
* The Devil's Snare is briefly important here and again in ''Order of the Phoenix''.
* Harry dreads encountering a fully-grown dragon on the way to the Philosopher's Stone. He doesn't, but in ''Goblet of Fire''...
* Harry realizes that he would be no match for Snape. When they duel at the end of ''Half-Blood Prince'', this is proven true.
* Dumbledore says that "humans do have a knack of choosing precisely those things that are worst for them." Even he is not immune to this, as in ''Half-Blood Prince'' [[spoiler:his desire to use the Resurrection Stone led him to impulsively try on Marvolo Gaunt's ring, causing him to be mortally cursed.]]
* Dumbledore says that Voldemort is not truly alive, and thus cannot be killed. The details of this are revealed in ''Half-Blood Prince''.
* Harry asks Dumbledore why Voldemort tried to kill him in the first place, but Dumbledore declines to answer. [[spoiler:The prophecy]] is revealed in ''Order of the Phoenix''.
* Dumbledore tells Harry that James saved Snape's life, the circumstances of which are revealed in ''Prisoner of Azkaban''. He also claims that this is why Snape protected Harry from Quirrell, though ''Deathly Hallows'' reveals that [[spoiler:he actually did it out of love for Lily.]]
* Hagrid gives Harry a photo album with pictures of his parents from their old school friends, one of whom was undoubtedly Remus Lupin, who first appears in ''Prisoner of Azkaban''.
* It is mentioned that Neville got good marks on his herbology exam. His interest and talent for the subject grows throughout the series until, by the epilogue of ''Deathly Hallows'', [[spoiler:he becomes the Hogwarts herbology professor.]]
* The students are given notes forbidding them from using magic over the summer holiday, presumably mentioning the Decree for the Reasonable Restriction of Underage Sorcery, which is a plot point later that summer in ''Chamber of Secrets'' and again in ''Order of the Phoenix''.
* Ron promises to send Harry a letter inviting him to stay. He later does, only to have it stolen by [[spoiler:Dobby]] before it can arrive prior to ''Chamber of Secrets''.
* In the last line of the book, Harry says he's "going to have a lot of fun with Dudley this summer..." ''Chamber of Secrets'' reveals that this is not the case, and that the Dursleys [[spoiler:immediately lock up all of his magical possessions.]]
[[/folder]]

[[folder:Harry Potter and the Chamber of Secrets]]
* Dobby almost speaks ill of the family he serves. They are later revealed to be the [[spoiler:Malfoys.]]
* Dobby warns Harry of a plot to make bad things happen at Hogwarts. This refers to [[spoiler:Lucius Malfoy, acting on orders given to him by Voldemort before his fall, to send his diary to Hogwarts to open the Chamber of Secrets and purge the school of Muggle-borns.]]
* Harry receives a warning letter from Mafalda Hopkirk of the Improper Use of Magic office. She also sends him a notice in ''Order of the Phoenix'' and is [[spoiler:impersonated by Hermione]] in ''Deathly Hallows''.
* Harry is threatened with expulsion should he perform any more magic, which is his fear in ''Prisoner of Azkaban'' and briefly happens in ''Order of the Phoenix''.
* The flying Ford Anglia is used to take Harry from the Dursley's house. Then again to fly to Hogwarts and [[spoiler:then to escape from the Acromantulas in the Forbidden Forest.]]
* Fred says that Muggle lock picking is worth learning. He and George later sell Muggle magic tricks [[spoiler:at their joke shop]] in ''Half-Blood Prince''.
* The Weasleys have a ghoul in their attic. It serves an important function in ''Deathly Hallows'', [[spoiler:disguised as a Spattergroit-infected Ron.]]
* George references Percy's strange behavior, which continues through the book. It is eventually revealed that [[spoiler:he has a girlfriend, Penelope Clearwater.]]
* Ron mentions Arthur's co-worker Perkins, who makes minor appearances in ''Order of the Phoenix'' and ''Deathly Hallows''.
* Gilderoy Lockhart first appears in a photograph on a book cover, and is later a major character throughout the book.
* Arthur mentions that Mundungus Fletcher tried to hex him during a raid. He is mentioned again in ''Goblet of Fire'' and then becomes an important character from ''Order of the Phoenix'' on.
* Ron has a fish tank full of frog spawn in his room. When Harry returns in ''Goblet of Fire'', he notes that this has grown into a large frog.
* When life at the Burrow is first described, we are told that "small explosions from Fred and George's bedroom were considered perfectly normal." In ''Goblet of Fire'', it turns out that the explosions were a side effect of the twins working on joke products they hope to eventually sell.
* The O.W.L.s are mentioned for the first time. They become important to the plot in ''Order of the Phoenix''.
* When Harry accidentally transports himself to Borgin and Burkes, he encounters a number of things that are important later in ''Half-Blood Prince''. First, he hides inside a large black cabinet and is careful to leave the door open a crack. Had he shut it all the way, he would have learned a few years early that it is a [[spoiler:Vanishing Cabinet with a twin located at Hogwarts.]] Draco examines a cursed opal necklace that "Has Claimed the Lives of Nineteen Muggle Owners to Date" and the Hand of Glory, both of which he will later use [[spoiler:in his attempt to assassinate Dumbledore.]] The store itself makes an important reappearance in ''Half-Blood Prince'', where we also learn that [[spoiler:Voldemort used to work there to gain access to rare heirlooms for Horcruxes.]]
* Lucius Malfoy arranges for Borgin to collect Dark Artifacts from Malfoy Manor, which is an important location in ''Deathly Hallows''.
* Fred, George, and Lee Jordan buy Filibuster Fireworks at Gambol and Japes. They shoot some off on the last day of vacation, George forgets the box when they are leaving to go to King's Cross, then he and Fred attempt to feed one to a Salamander at Halloween, and finally [[spoiler:Harry uses one to create a diversion in Potions class so Hermione can obtain the last two ingredients they need for the Polyjuice Potion.]]
* Ron tells Hermione and Harry that Percy wants to be Minister for Magic. Percy embarks on his Ministry career in ''Goblet of Fire'' and Hermione [[spoiler:actually becomes the Minister for Magic by the time of ''Cursed Child''.]]
* The inconsiderate ''Daily Prophet'' photographer is identified as Bozo and accompanies Rita Skeeter in ''Goblet of Fire''.
* Draco calls Ginny Harry's girlfriend. They end up dating in ''Half-Blood Prince'' and [[spoiler:get married]] before the epilogue of ''Deathly Hallows''.
* Lucius picks up Ginny's copy of ''A Beginner's Guide to Transfiguration'' and returns it to her cauldron. It is later revealed that he also [[spoiler:slipped Tom Riddle's diary into her stack of books.]]
* The spell Arthur used to enlarge the interior of the car is an Undetectable Extension Charm, which shows up later on, most notably with Hermione's handbag in ''Deathly Hallows'' and Newt Scamander's suitcase in the ''Fantastic Beasts'' film.
* The Weasleys have to stop because Ginny forgot her diary, [[spoiler:or, more accurately, Tom Riddle's diary,]] at home.
* When Harry and Ron try to get to Platform 9 3/4, the barrier is blocked. They later learn this was done by [[spoiler:Dobby]].
* Ron mentions Apparition by name, which later becomes an important method of transportation later in the series.
* The Hogwarts Express Trolley Witch receives another mention. She does not get any expansion until ''Cursed Child''.
* Ron crashes the flying Ford Anglia into the Whomping Willow, which becomes far more significant in ''Prisoner of Azkaban''.
* Harry and Ron miss Ginny being sorted in Gryffindor. They also miss the sortings of Luna Lovegood (Ravenclaw) and Zacharias Smith (Hufflepuff) who first appear in ''Order of the Phoenix''.
* Ron speculates that Snape was sacked. In ''Deathly Hallows'', [[spoiler:Snape's tenure as Headmaster comes to an end when he is "sacked" by the Heads of House.]]
* Harry notices Dumbledore's "very crooked" nose, which is explained in ''Deathly Hallows''.
* The second years repot Mandrakes in their first Herbology lesson. Hermione explains their curative effects, which is critically important later in the book [[spoiler:to restore those petrified by the basilisk]] and the fatal cries of adult Mandrakes, which comes up again in ''Deathly Hallows'' [[spoiler:when they're used as part of the defensives measures during the Battle of Hogwarts]].
* Justin Finch-Fletchley makes his first appearance in this lesson a while before he has an impact on the plot.
* Ron's broken wand, with spells backfiring on him, is mostly used for comic relief throughout the book. However, it ultimately [[spoiler:saves Ron' and Harry's memories when Lockhart attempts to obliviate them with it.]]
* Ron's [[spoiler:jealous]] rage over Hermione's crush on Lockhart is the first hint at [[spoiler:his attraction to her]] that develops across the series.
* Ron angrily tells Malfoy to "eat slugs." He later attempts to curse him with a spell that does just that, only to have it backfire.
* Lockhart brings Cornish Pixies to class. Cornwall is where Shell Cottage is located in ''Deathly Hallows'' and it is the childhood home of Muggle private detective [[Literature/CormoranStrikeNovels Cormoran Strike]].
* Hermione can't believe that Lockhart is an inept teacher and wizard, she talks about the amazing things he has done. Ron retorts with "He ''says'' he's done." [[spoiler:Lockhart himself reveals that he's a fraud, going to the real people who have done the heroic deeds, listening to the exact details and then wiping their memories clean with his speciality, the Memory Loss Charm.]]
* Draco Malfoy calls Hermione "filthy little Mudblood" and it is stressed upon how highly offensive the term is to Muggleborns. In ''Order of the Phoenix'', we learn that, in the past, [[spoiler:Snape called Harry's mother that, which was the catalyst for half the events in the series.]]
* Hagrid tells the trio that the Defense Against the Dark Arts position is rumored to be jinxed. Sure enough, no teacher holding that post lasts for more than one school year throughout the series. In ''Half-Blood Prince'', we learn that [[spoiler:Voldemort himself cursed the job when he was denied it.]]
* Ron alludes to the concept of pure-blood supremacy, which is important later in the book and is a central tenet of the Death Eaters' philosophy later in the series.
* Hagrid's expulsion from Hogwarts is brought up again, and is explained later in the book.
* Lockhart receives fan mail from Gladys Gudgeon, who continues to do so in ''Order of the Phoenix'' [[spoiler:after he's been erased of his memories, exposed as a fraud, and permanently institutionalized in St. Mungo's.]]
* During his detention with Lockhart, Harry hears a voice talking about killing. [[spoiler:This is coming from the basilisk slithering around in the pipes.]]
* Dumbledore inspects the petrified Mrs. Norris with his wand, which, as we learn in ''Deathly Hallows'', is the Elder Wand.
* Ron mentions vomiting slugs all over an Award for Special Services to the School during his detention with Filch. This trophy, as he later remembers, was awarded to Tom Riddle, A.K.A. [[spoiler:Voldemort]].
* At the beginning of October, Ginny is mentioned to be looking pale. This is the first of many signs that something is not quite right with her.
* Peeves smashes a Vanishing Cabinet, [[spoiler:the twin of the one in Borgin and Burkes]], which comes up again in ''Order of the Phoenix'', and then is critical to the plot of ''Half-Blood Prince'', [[spoiler:when Malfoy spends all year mending it to use in his attempt to assassinate Dumbledore.]]
* Fred and George steal a salamander from their Care of Magical Creatures class. Not only do the trio begin taking this class in ''Prisoner of Azkaban'', the current professor Silvanus Kettleburn retires and is replaced by [[spoiler:Hagrid.]]
* Hermione says that Moaning Myrtle's bathroom has been closed all year because she keeps flooding it. Not only is Myrtle [[spoiler:a victim of the basilisk]], the bathroom was flooded by [[spoiler:the basilisk itself.]] The bathroom itself is vastly important later in the book, as the trio uses it to [[spoiler:brew Polyjuice Potion]] and it contains [[spoiler:the entrance to the Chamber of Secrets.]]
* The spiders acting strangely eventually leads Harry and Ron to [[spoiler:Aragog]] and is a sign of the [[spoiler:Basilisk.]]
* Polyjuice Potion is used relatively innocently here, but later in the series it becomes an important tool for good and for evil.
* Dobby tells Harry that if he can only be freed if his masters present him with clothes, and that if he was presented with even a sock, he would be free to leave his masters' house for ever. At the end, [[spoiler:Harry tricks Lucius Malfoy into doing just that, releasing Dobby from servitude.]]
* Dumbledore says the question is not ''who'' opened the Chamber of Secrets again, but ''how''. He already knows that [[spoiler:Tom Riddle opened it in the first place, he just doesn't have any evidence to prove it, and can't explain how he's managed it this time.]]
* "Talismans, amulets, and other protective devices" become very popular at Hogwarts after the Chamber is opened. This happens again in the wider wizarding world in ''Half-Blood Prince'' after [[spoiler:Voldemort's return.]]
* Seamus says that dueling lessons "might come in handy one of these days..." Indeed they do, when [[spoiler:the Second Wizarding War begins.]]
* Harry learns his signature spell - Expelliarmus, the Disarming Charm - from Snape, of all people, at the Dueling Club.
* After Ron and Hermione learn Harry is a Parselmouth, they worry that people will think he's Salazar Slytherin's "great-great-great-great-grandson." He's not, but [[spoiler:the piece of Voldemort's soul living in him is indeed descended from Slytherin.]]
* Hagrid speculates that his roosters were killed by foxes or a Blood-Sucking Bugbear. They were actually killed by [[spoiler:Ginny.]]
* Previous Hogwarts Headmasters appear sleeping in their portraits. These include Armando Dippet (who is important in the backstory of this book), Dilys Derwent and Dexter Fortescue (who are important in [[spoiler:saving Arthur Weasley's life]] in ''Order of the Phoenix''), and Phineas Nigellus Black (who becomes very important in ''Deathly Hallows'').
* Harry encounters the Sorting Hat again. It shows up later in the book during a critical moment.
* When Harry meets Fawkes, Dumbledore explains that Phoenixes can carry enormous weight and their tears have healing powers, both of which are very useful later in the book. They also regularly die and then return to life, which allows Fawkes to [[spoiler: intercept Voldemort's Killing Curse meant for Dumbledore in ''Order of the Phoenix''.]] Fawkes himself is the Phoenix who [[spoiler:gave the feathers for Voldemort' and Harry's wands,]] as revealed in ''Goblet of Fire''.
* While disguised as Crabbe and Goyle, Ron and Harry run into a Ravenclaw girl who later turns out to be Penelope Clearwater, [[spoiler:who gets petrified by the basilisk.]] She was also in the general vicinity of Percy, [[spoiler:who she is dating.]]
* A ''Daily Prophet'' article mentions that Lucius Malfoy is one of the Hogwarts governors, which is important later in the book for [[spoiler:getting Dumbledore suspended as Headmaster.]]
* Malfoy says that the last time the Chamber was opened, a Muggle-born died. This turns out to be [[spoiler:Moaning Myrtle.]]
* Malfoy is the first to mention Azkaban, the wizard prison. [[spoiler:Hagrid]] is sent here later in the book, and, obviously, it becomes important from ''Prisoner or Azkaban'' on.
* Malfoy unknowingly reveals to Harry and Ron that Malfoy Manor has a "secret chamber under the drawing-room floor." This is used in ''Deathly Hallows'' to [[spoiler:imprison Ollivander, Luna, Griphook, Dean Thomas, and, briefly, Harry and Ron.]]
* The trio discovers the diary of T.M. Riddle in the bathroom. This turns out to be [[spoiler:the thing responsible for Ginny opening the Chamber of Secrets]], and, as we learn in ''Half-Blood Prince'', [[spoiler:one of Voldemort's Horcruxes.]] T.M. Riddle is revealed to be [[spoiler:Voldemort himself.]]
* Ron jokes that Riddle earned his Award for Special Services to the School by killing Myrtle. In fact, [[spoiler:he actually ''is'' directly responsible for her death.]]
* Lockhart mentions Love Potions on Valentine's Day, and they become very important in ''Half-Blood Prince'' when [[spoiler:Ron drinks one]] and we learn [[spoiler:Voldemort was conceived under its influence.]]
* Ginny is noted to be horrified when Malfoy takes the diary from Harry. She later [[spoiler:ransacks the second year boys' dormitory to retrieve it.]]
* Riddle tells Harry that he stored his memories in the diary in a "more lasting way than ink." In ''Half-Blood Prince'', the method is revealed to be [[spoiler:storing a piece of his soul in it.]]
* Harry travels into Riddle's memory. This type of magic becomes important from ''Goblet of Fire'' on with Dumbledore's Pensieve.
* Riddle talks about his early years to Professor Dippet and, later in the book, to Harry. This is greatly expanded upon in ''Half-Blood Prince''.
* In Riddle's memory, Harry catches a glimpse of Aragog, who is important later in the book.
* The second years sign up for third year electives. Harry and Ron take the same classes, which are revealed in ''Prisoner of Azkaban'' to be Divination and Care of Magical Creatures, while Hermione signs up for them all, [[spoiler:and will receive a Time-Turner in able to accomplish this.]]
* Percy advises Harry to play to his strengths, and Harry feels that his only strength is Quidditch. A similar exchange takes place with far more importance between Harry and Professor Moody in ''Goblet of Fire'' prior to the First Task.
* Hermione rushes off to the library after Harry hears the voice again, and she gets petrified. We later learn that she [[spoiler:tore out a page on Basilisks and was on her way back, checking around corners with a mirror when she and Penelope Clearwater were attacked.]]
* When Percy finds out about Penelope Clearwater, he is left in shock, presumably because he didn't think the monster would dare attack a prefect. We later learn that [[spoiler:she is actually Percy's girlfriend.]]
* Harry's Invisibility Cloak makes another appearance. It becomes even more important in ''Deathly Hallows'' when we learn that [[spoiler:it's one of the Deathly Hallows.]]
* Hagrid accuses Lucius Malfoy of threatening and blackmailing the other Hogwarts governors. [[spoiler:This turns out to be exactly the case.]]
* Lucius mentions the "Azkaban guards," i.e. the Dementors, who make their first appearance in ''Prisoner of Azkaban''.
* Dumbledore says that he'll only truly be gone when no one left is loyal to him, and that help will always be given at Hogwarts to those who ask for it. This is important later in the book.
* Lucius says that hopefully Dumbledore's successor will be able to prevent any killings. In ''Deathly Hallows'', [[spoiler:his legitimate successor Snape discreetly tries to protect students from the Carrows.]]
* After Dumbledore's suspension, Malfoy suggests to Snape that he should apply for the position of Headmaster. In ''Deathly Hallows'', [[spoiler:this is where he winds up.]]
* Ron is scared that there are werewolves in the Forbidden Forest. This is another instance of the ignorance and prejudice faced by werewolves that becomes apparent in ''Prisoner of Azkaban''.
* Harry mentions the centaurs, who become important in ''Order of the Phoenix''.
* Percy reveals that Ginny walked in on him doing something embarrassing, later revealed to be [[spoiler:kissing his girlfriend Penelope.]]
* Harry and Ron hide in the staffroom wardrobe. A boggart takes up residence there in ''Prisoner of Azkaban''.
* Myrtle mentions having haunted her former bully Olive Hornby after becoming a ghost. This is expanded upon in ''Goblet of Fire''.
* Riddle tells Harry about Ginny's crush on him, which is important from ''Half-Blood Prince'' on.
* Riddle falsely claims Hagrid used to raise werewolf cubs under his bed. [[spoiler:Voldemort]] tells the same bigoted joke in regards to the marriage of Lupin and Tonks in ''Deathly Hallows''.
* Riddle says Dumbledore never like him as much as the "other teachers," one of whom was Horace Slughorn, a major character in ''Half-Blood Prince''.
* Voldemort's true name is revealed to be Tom Marvolo Riddle. His namesakes, Tom Riddle Sr. and Marvolo Gaunt, become important in ''Half-Blood Prince'' via memories.
* Riddle mentions his "most intimate friends," who are revealed in ''Half-Blood Prince'' to have been the earliest Death Eaters and included Antonin Dolohov and Nott as well as the elder Lestrange, Rosier, Avery, and Mulciber.
* We learn in ''Deathly Hallows'' that Gryffindor's sword was imbued with Basilisk venom, which enables them to use it to [[spoiler:destroy other Horcruxes, specifically the ring, the locket, and the snake.]]
* Ron and Hermione return to the Chamber of Secrets in ''Deathly Hallows'' to retrieve a Basilisk fang [[spoiler:and destroy Hufflepuff's cup.]]
* Dumbledore's sources tell him that Voldemort is currently hiding in the forests of Albania. In ''Goblet of Fire'', this is where [[spoiler:Peter Pettigrew reunites with Voldemort and captures Bertha Jorkins, leading to the plan that results in Voldemort's resurrection]]. The nation is mentioned again in ''Deathly Hallows'', as this is where [[spoiler:Helena Ravenclaw hid her mother's diadem, and where Voldemort traveled to turn it into a Horcrux.]]
* Dumbledore says that Voldemort underwent "dangerous, magical transformations" in the past, which we learn in ''Half-Blood Prince'' to be [[spoiler:splitting his soul into pieces.]]
* Dumbledore tells [=McGonagall=] to alert the kitchens for a feast. In ''Goblet of Fire'', we learn that it is staffed by house-elves, and [[spoiler:Dobby becomes employed there.]]
* Dumbledore tells Harry that he suspects a part of Voldemort may live inside him. In ''Deathly Hallows'', [[spoiler:this proves true and Harry turns out to be an unintentional Horcrux.]]
* Dumbledore points out that only a true Gryffindor could pull Godric Gryffindor's sword out of the Sorting Hat. In ''Deathly Hallows'', [[spoiler:Neville definitively proves that he belongs in Gryffindor when he summons the sword and kills Voldemort's final Horcrux (which is also a snake).]]
* Dumbledore says that he needs to hire a new Defense Against the Dark Arts Professor. In ''Prisoner of Azkaban'', he ends up hiring Remus Lupin.
* Dobby reappears in ''Goblet of Fire'', becoming an important character from then on.
* The last we hear of Lockhart, he's being sent off to get his memories back. When he reappears at St. Mungo's in ''Order of the Phoenix'', he's not much better off.
* At the end, Harry gives Ron the Dursleys' telephone number. Ron ends up calling at the beginning of ''Prisoner of Azkaban'', with disastrous results.
[[/folder]]

[[folder:Harry Potter and the Prisoner of Azkaban]]
* On the first page, Harry is reading ''A History of Magic'' by Bathilda Bagshot, who becomes important in ''Deathly Hallows''.
* The newspaper photo of the Weasley family's vacation to Egypt [[spoiler:is used by Sirius Black to realize Peter Pettigrew is alive,]] and thus is the catalyst for the entire plot of the book.
* Ron gives Harry a Pocket Sneakoscope for his 13th birthday, claiming it kept going off because Fred and George put beetles in Bill's soup. It was actually going off because [[spoiler:Scabbers is Peter Pettigrew in disguise.]] It continues to do this when [[spoiler:Scabbers]] is around, so Harry assumes that it is defective, when its actually working perfectly.
* Hermione mentions studying the "local history of witchcraft" in France, which undoubtedly includes Beauxbatons Academy of Magic, which becomes important in ''Goblet of Fire''.
* Hagrid sends Harry ''The Monster Book of Monsters'', hinting that it will come in handy. Hagrid is later revealed [[spoiler:to have been hired as the Care of Magical Creatures Professor.]]
* Harry learns that he needs a guardian's signature to go to Hogsmeade. These trips become important to the plot, and his his signature is eventually supplied by [[spoiler:Sirius Black.]]
* Sirius Black is mentioned on a Muggle news broadcast. He is soon revealed to be the eponymous prisoner of Azkaban, and is a major character in the series. Vernon notes that he "could be coming up the street right now." We retroactively learn that [[spoiler:that's exactly where he is.]]
* Harry recalls that he will be expelled if he performs any more magic outside of school. He gets excused this time, but not in ''Order of the Phoenix''.
* Harry sees something menacing him in Magnolia Crescent. It is later identified as a black dog, presumed to be a Grim, but eventually revealed to be [[spoiler:Sirius Black.]]
* It is mentioned that Cornelius Fudge informed the Muggle Prime Minister of Black's escape. The Prime Minister shows up again in ''Half-Blood Prince''.
* When discussing accused Death Eater Sirius Black, Stan Shunpike claims that he'd rather blow himself up than go to Azkaban. Come ''Half-Blood Prince'', [[spoiler:he is arrested on suspicion of being a Death Eater.]]
* Stan mentions the Azkaban guards, AKA Dementors, who are important later in the book and the series.
* Fudge says he's sure that Harry and the Dursleys care for each other "''very'' deep down." He is proven somewhat correct in ''Deathly Hallows'', during their [[spoiler:awkward farewell.]] ''Pottermore'' reveals that Harry and Dudley are on "Christmas card terms" afterwards and occasionally visit. ''Cursed Child'' reveals that Petunia [[spoiler:kept the blanket Harry was delivered in. Dudley sends it to him after Petunia passes away.]]
* Someone mentions that the Irish national Quidditch team is a favorite for the World Cup. The World Cup takes place during ''Goblet of Fire'', and Ireland beats Bulgaria and wins.
* Harry sees the Firebolt in Diagon Alley, and later gets one for Christmas [[spoiler:from Sirius after his Nimbus 2000 is smashed]], using it throughout the series.
* Harry asks Hermione if she's planning on eating or sleeping. Indeed, taking all the classes [[spoiler:via time travel]] takes it toll on her over the course of the year.
* Ron mentions that Scabbers isn't looking well. This is because [[spoiler:he's terrified because Sirius Black is looking for him.]]
* There are "funny custard-coloured furballs that were humming loudly" at the Magical Menagerie. Puffskeins receive an entry in the ''Fantastic Beasts'' book and Fred and George breed Pygmy Puffs from them in ''Half-Blood Prince''.
* Crookshanks immediately despises Scabbers. This is because [[spoiler:he can sense that Scabbers is actually a human Animagus.]]
* Ginny's crush on Harry is mentioned again. They start dating in ''Half-Blood Prince'' and [[spoiler:get married]] by the epilogue of ''Deathly Hallows''.
* Arthur says that if Black could break out of Azkaban, he could break into Hogwarts. Later in the book, [[spoiler:he does.]]
* Molly mentions having once brewed a love potion. Love potions become important in ''Half-Blood Prince''.
* Black muttering "He's at Hogwarts" in his sleep seems to refer to Harry, but he's actually talking about [[spoiler:Peter Pettigrew.]]
* The alleged jinx on the Defense Against the Dark Arts post is mentioned again. We learn in ''Half-Blood Prince'' that [[spoiler:Voldemort jinxed it.]]
* Professor R.J. Lupin initially just seems to be the new Defense Against the Dark Arts Professor. We later learn that he has a connection to Harry's parents and [[spoiler:Sirius Black]], and that he is [[spoiler:a werewolf.]]
* Harry hides his Pocket Sneakoscope in a pair of Vernon's socks. He later gives these to Dobby for Christmas in ''Goblet of Fire''.
* Hermione mentions the Shrieking Shack, which is an important location later in the book and again in ''Deathly Hallows''.
* The Trolley Witch makes another appearance. She is expanded in ''Cursed Child''.
* The Dementor causes Harry to hear someone screaming, later revealed to be [[spoiler:a memory of his mother's death.]]
* Lupin conjures a "silvery thing, which turns out to be a Patronus Charm, which is important later in the book and throughout the series.
* Harry notes that the stagecoaches are presumably pulled by invisible horses. The Thestrals make their first visible appearance in ''Order of the Phoenix''.
* Professor [=McGonagall=] briefly meets with Hermione regarding her schedule. We later learn that she [[spoiler:gave her a Time-Turner and told her how to use it.]]
* Harry again notices Dumbledore's "extremely crooked" nose, which is explained in ''Deathly Hallows''.
* Dumbledore mentions Silvanus Kettleburn, the former Care of Magical Creatures Professor. He gets some characterization in the commentary of ''The Tales of Beedle the Bard''.
* Harry notices that Snape is glaring at Lupin with a look that is "beyond anger." Their history is elaborated later in the book and in ''Order of the Phoenix''.
* The feast magically appears, as usual. We learn in ''Goblet of Fire'' that this is done by house-elves, with [[spoiler:Dobby]] joining the staff at some point this year.
* Hermione is taking Muggle Studies. This class is taught by Charity Burbage, who is [[spoiler:murdered by Voldemort]] in ''Deathly Hallows''.
* Sir Cadogan makes an appearance leading the trio to North Tower a while before he [[spoiler:temporarily replaces the Fat Lady.]]
* Professor Trelawney says that books can only take you so far in Divination, worrying Hermione. [[spoiler:Hermione proves not to have the Sight and eventually quits.]]
* Trelawney tells Parvati Patil to beware a red-haired man. Her sister Padma ends up having a bad time at the Yule Ball with Ron in ''Goblet of Fire''.
* Trelawney predicts that "around Easter, one of our number will leave us forever." This ends up referring, not to Harry dying, but to [[spoiler:Hermione, who drops the class.]]
* Ron suggests that Harry's tea leaves indicate that he will work for the Ministry of Magic. According to ''Pottermore'', [[spoiler:he becomes an Auror]] and by ''Cursed Child'', [[spoiler:he has become the Head of the Department of Magical Law Enforcement.]] Ron also says that Harry will get an unexpected windfall, which comes true in ''Goblet of Fire'' when [[spoiler:he wins 1,000 Galleons in the Triwizard Tournament.]]
* Professor [=McGonagall=] teaches the third years a lesson on Animagi, which end up being immensely important to the plot.
* Hagrid laments that he should have started with flobberworms instead of hippogriffs. Flobberworms end up being the class's subject for the majority of the year.
* Professor Lupin says that no one knows what a boggart looks like in its natural state. In ''Order of the Phoenix'', Mad-Eye Moody is able to do this with his magical eye.
* One of Harry's worst fears is Voldemort returned to full strength. In ''Goblet of Fire'' [[spoiler:this fear is realized.]]
* Lupin's worst fear is a "silvery-white orb," which turns out to be [[spoiler:the full moon.]]
* Lupin teaches the third years about grindylows. Harry ends up getting attacked by a swarm of them in ''Goblet of Fire''.
* Snape makes Lupin a potion. It turns out to be a Wolfsbane Potion, which [[spoiler:gives werewolves control over their actions.]]
* Cedric Diggory makes a fairly unimportant first appearance as the Hufflepuff Quidditch Captain and Seeker. He becomes a major character in ''Goblet of Fire'' [[spoiler:and again, posthumously]], in ''Cursed Child''.
* Snape substitute teaches Defense Against the Dark Arts several times. In ''Half-Blood Prince'', [[spoiler:he gets the job full time.]]
* Snape teaches the third years about werewolves, and we later learn that [[spoiler:he was intentionally doing this in an attempt to out Lupin.]]
* Snape incorrectly notes that kappas are found in Mongolia. This comes up in the ''Fantastic Beasts'' book, which states that they are native to Japan and has an annotation from Ron asserting that "Snape hasn't read this."
* Dumbledore's wand is mentioned, but its importance isn't revealed until ''Deathly Hallows''.
* Lupin says that the Whomping Willow was planted the same year he came to Hogwarts. We later learn that he was the reason it was planted in the first place.
* Lupin tells Harry that dementors affect him strongly because there are "horrors in his past that the others don't have." In ''Deathly Hallows'', we learn that [[spoiler:this isn't Harry's memory, it's the memory of Voldemort's Horcrux.]]
* Harry is happy at "the thought that he might never have to hear his mother's death again." In ''Cursed Child'', [[spoiler:he has to listen to it in person.]]
* Messrs. Moony, Wormtail, Padfoot, and Prongs all turn out to be established characters. They are [[spoiler:Lupin, Scabbers (A.K.A. Peter Pettigrew), Sirius Black, and Harry's father.]]
* Fudge mentions that Dumbledore was tipped off about Voldemort going after the Potters by a spy. In ''Deathly Hallows'', this spy is revealed to have been [[spoiler:Snape.]]
* Fudge refers to "Hit Wizards" working for the Department of Magical Law Enforcement. They are identified as Aurors in ''Goblet of Fire''.
* Fudge mentions having given his newspaper to Sirius Black during his visit to Azkaban. This was actually critical to the plot, as this was where Sirius first saw the photo of Scabbers.
* Fudge says "I shudder to think how quickly he'll rise again" if Voldemort is joined by a devoted servant. In ''Goblet of Fire'', [[spoiler:Voldemort regains his body a year after being found by Pettigrew.]]
* All that was left of Peter Pettigrew after Black killed him was his finger. We later learn that [[spoiler:this is because he cut it off himself and turned into a rat.]]
* Harry notes that, thanks to Black, he's never spoken to his parents. In ''Deathly Hallows'', [[spoiler:he uses the Resurrection Stone and able to speak with them for the first time.]]
* Trelawney claims that when 13 dine, the first to rise will be the first to die. When she enters the Dining Hall, there are 12 seated at the table. However, [[spoiler:Pettigrew is in Ron's pocket at the time, making it 13. Dumbledore rises to greet Trelawney, and he dies]] in ''Half-Blood Prince''.
* Hermione asserts that Harry' Firebolt was sent by Sirius Black. [[spoiler:It turns out she's right, but for the wrong reasons.]]
* When Harry and Ron discuss Lupin's health, Hermione says it's obvious what's wrong with him. It is later revealed that [[spoiler:she's known Lupin is a werewolf ever since Snape's lesson.]]
* Lupin explains the Dementor's Kiss to Harry. This ends up happening off-page to [[spoiler:Barty Crouch Jr.]] in ''Goblet of Fire'' and is explicitly described in ''Cursed Child'' happening to [[spoiler:the alternate timeline Snape, Hermione, and Ron.]]
* Neville mentions having dropped a list of Sir Cadogan's passwords. This is very important later when [[spoiler:Sirius Black uses it to get into Gryffindor Tower.]]
* Cho Chang has a minor appearance as the Ravenclaw Seeker before taking on a larger role starting in ''Goblet of Fire''.
* Ron says that a very rough crowd of ghosts lives in the Shrieking Shack. We later learn that [[spoiler:these are just rumors spread due to the monthly presence of a werewolf there for seven years in the '70s.]]
* Snape uses Floo Powder to contact Lupin. This method of communication becomes important from ''Goblet of Fire'' on.
* After coming to terms with Scabbers' presumed death, Ron remarks that his parents might get him an owl. He ends up getting one, Pigwidgeon, from [[spoiler:Sirius Black]] at the end of the book.
* Harry has a nightmare where he has to avoid the Slytherin team's dragons on his broomstick. Something similar ends up happening during the First Task in ''Goblet of Fire''.
* Montague is one of the Slytherin Chasers. He has a somewhat larger role in ''Order of the Phoenix'' [[spoiler:involving being shoved into a Vanishing Cabinet]], which ends up being critical to the plot of ''Half-Blood Prince''.
* Walden Macnair, the Ministry executioner, is revealed to be a Death Eater in ''Goblet of Fire'', and he is responsible for [[spoiler:getting the giants to ally with Voldemort]] in ''Order of the Phoenix''.
* Trelawney makes a prophecy that "the servant will break free," which happens when [[spoiler:Pettigrew's identity is revealed and he flees]], and that "the Dark Lord will rise again," which happens in ''Goblet of Fire''.
* Lupin refers to the fact that Animagi can be unregistered. Another of these, [[spoiler:Rita Skeeter]], appears in ''Goblet of Fire''.
* Lupin believes that Snape was jealous of James for his Quidditch skills. In ''Deathly Hallows'', we learn that he was indeed jealous, but of [[spoiler:James's relationship with Lily Evans.]]
* Lupin calls out Snape for his willingness to send Sirius to Azkaban over a "schoolboy grudge." In ''Deathly Hallows'', it becomes apparent that [[spoiler:he believes Sirius was responsible for the death of the woman he loved.]]
* Harry asks Sirius if he has a house. His family home, 12 Grimmauld Place, makes its debut in ''Order of the Phoenix''.
* Harry tries to encourage Hermione to cast a Patronus. This is unsuccessful, but in ''Order of the Phoenix'', he not only teaches Hermione the spell, but many other students as well.
* Hermione says that the Time-Turner came from the Ministry of Magic. We see its specific point of origin, the Department of Mysteries, in ''Order of the Phoenix''.
* Hermione says that not changing time is "one of the most important Wizarding laws." In ''Cursed Child'', [[spoiler:Delphini breaks this law in an attempt to bring back Voldemort.]]
* Fudge fears that he will become a laughingstock over Sirius Black's escape. He does end up going down as one of the worst Ministers for Magic by the time of ''Half-Blood Prince'', but because he [[spoiler:stuck his head in the sand during Voldemort's return.]]
* Fudge says that the dementors were out of control when they attempted to Kiss Harry. This hints at how little control the Ministry has over them, and they end up [[spoiler:siding with Voldemort]] in ''Half-Blood Prince''.
* Fudge suggests stationing dragons outside of Hogwarts. The Ministry does end up sending four dragons to the school in ''Goblet of Fire'' for the Triwizard Tournament.
* Dumbledore tells Harry that Professor Trelawney's prediction was the second true prophecy she's ever made. The first one, revealed in ''Order of the Phoenix'', turns out to be crucial to the plot of the series.
* Dumbledore says that Harry spared Pettigrew's life, he owes him a life debt. This comes up again in ''Deathly Hallows'' [[spoiler:and causes Pettigrew to die.]]
* After Lupin's resignation, Dean Thomas suggests that the next Defense Against the Dark Arts professor will be a vampire. What they end up getting, [[spoiler:a crazed Death Eater in disguise]], in ''Goblet of Fire'' turns out to be worse.
* Ron says that the Quidditch World Cup is taking place over the summer and that his father will probably get tickets. The World Cup is an important event in ''Goblet of Fire''.
[[/folder]]

[[folder:Harry Potter and the Goblet of Fire]]
* The themes of British small town history and local intrigue that surround Little Hangleton in the opening of the book would later be the subject of ''Literature/TheCasualVacancy'', which is set another Muggle village called Pagford.
* The death of Tom Riddle Sr. is important later in the book [[spoiler:as his bones are used to resurrect his son.]]
* Nagini appears as Voldemort's pet snake. However, she has a more important role in ''Order of the Phoenix'', and in ''Half-Blood Prince'', we learn that [[spoiler:she is one of his Horcruxes.]]
* It is revealed that Peter Pettigrew abducted Bertha Jorkins and that Voldemort murdered her. Her disappearance is important throughout the book, and the information he extracted from her lead to [[spoiler:his return to power at the end.]]
* Voldemort refers to his "''faithful'' servant" rejoining him. We later learn he means [[spoiler:Barty Crouch Jr.]]
* Voldemort casually mentions that Bertha had already been under the influence of a memory charm. The person who previously modified her memory is later identified as [[spoiler:Barty Crouch Sr.]]
* Voldemort tells Frank Bryce not to lie to him because "he always knows." His mastery of Legilimency is explained in ''Order of the Phoenix''.
* Voldemort kills Frank Bryce with "a flash of green light," same as Harry's parents. Later in the book, this is identified as the Killing Curse.
* The significance of Harry's scar hurting is not fully explained until ''Deathly Hallows''.
* Harry has a brief fear of Voldemort coming for him at Privet Drive, and then comments about how the sleeping Dursleys are no help to him awake. In ''Order of the Phoenix'', we learn that [[spoiler:Petunia's presence protects Harry from Voldemort due to sharing her sister's blood.]]
* Dumbledore's nose is described as long and crooked. The story of how it was broken is told in ''Deathly Hallows''.
* Petunia is described as looking out the window "as though there had been a warning about an escaped rhinoceros." In the ''Fantastic Beasts'' film, Newt Scamander recaptures an escaped erumpent, which strongly resembles a rhino.
** This could also be a ShoutOut to [[Literature/JamesAndTheGiantPeach James and the Giant Peach]], in which an escaped rhinoceros [[DoesThisRemindYouOfAnything kills James's parents, forcing him to live with his horrible aunts.]]
* Ron says Fred and George want to open a joke shop. In ''Half-Blood Prince'', they do just that.
* Percy's boss, Mr. Crouch, is mentioned early on. He ends up becoming a very important character in the book.
* Percy says that the Department of International Magical Cooperation is busy planning a "top-secret" event right after the World Cup. This is later revealed to be the Triwizard Tournament.
* Viktor Krum is mentioned as one of the Quidditch players who will be participating in the World Cup. He ends up becoming an important character.
* Molly mentions the Apparition test. In ''Half-Blood Prince'', the trio take Apparition lessons.
* Molly uses Accio, the Summoning Charm, to confiscate Fred and George's toffees. The spell becomes very important later in the book and the rest of the series.
* Portkeys are innocently used to transport groups of people to the World Cup. A Portkey ends up being crucial to [[spoiler:Voldemort's resurrection]] later on.
* Cedric Diggory makes a minor appearance using the same Portkey as the Weasleys, but becomes a major character later in the book.
* Amos Diggory says that the Lovegoods have been at the World Cup for a week. Luna Lovegood becomes a major character starting in ''Order of the Phoenix'', and her father Xenophilius appears in ''Deathly Hallows''.
* Harry mentions the Dursleys' neighbor Mrs. Figg. [[spoiler:Dumbledore]] later mentions her at the end of the book as one of the "old company," and in ''Order of the Phoenix'', [[spoiler:she is revealed to be a Squib.]]
* Arthur mentions his coworker Perkins, who makes an appearance in ''Order of the Phoenix''.
* Several American witches are seen at the World Cup campground. The American wizarding community is a major focus of the ''Fantastic Beasts'' film.
* Harry sees Cho Chang at the campground, and she becomes important later on.
* Ron says that Bill had a penfriend from "a school in Brazil." This school, Castelobruxo, was later detailed on ''Pottermore''.
* It finally dawns on Harry that there are other schools of magic besides Hogwarts. Two of them, Beauxbatons and Durmstrang, are very important later in the book, and the others (Ilvermorny, Koldovstoretz, Castelobruxo, Uagadou, and Mahoutokoro) were later revealed on ''Pottermore''.
* Arthur points out Bode and Croaker at the campground and mentions that they work for the Department of Mysteries. The Department is majorly important in ''Order of the Phoenix'', and Broderick Bode has an expanded role there as well. Saul Croaker is mentioned in ''Cursed Child''.
* Barty Crouch Sr. is described "as though he wanted to leave nobody in doubt that all his ancestors had abided strictly by the law. We later learn that this is because [[spoiler:his own son most certainly did not, and the scandal destroyed his career.]]
* Harry mistakes Winky the house-elf for Dobby. Dobby makes his reappearance later in the book, and remains important for the rest of the series.
* Winky sits next to an empty seat on the pretense of saving it for her master. It is later revealed that [[spoiler:Barty Crouch Jr. was there the whole time under an invisibility cloak.]]
* Fudge mentions that Lucius Malfoy made a donation to St. Mungo's Hospital for Magical Maladies and Injuries. The hospital makes an appearance in ''Order of the Phoenix''.
* A group of Beauxbatons students mention Madame Maxime, who appears later in the book.
* Hermione informs Harry about Beauxbatons Academy of Magic, which is important later on.
* Harry loses his wand and assumes he dropped it. It is later revealed that [[spoiler:Barty Crouch Jr. stole it when they were in the top box.]]
* Winky is moving "as though someone invisible were trying to hold her back," which we later learn [[spoiler:is exactly the case.]]
* Hermione first becomes annoyed at the mistreatment of house-elves, which later leads her to found the Society for the Protection of Elvish Welfare.
* The group passes several goblins cackling over a sack of gold. It is later revealed that [[spoiler:they just robbed Ludo Bagman, who owes them a lot of gold.]]
* Amos Diggory uses ''Prior Incantato'' to investigate Winky's presumed use of Harry's wand. This effect is critically important during [[spoiler:the duel between Harry and Voldemort.]]
* Crouch dismisses Winky from his service for seemingly petty reasons. We learn later that he had much better excuse, [[spoiler:namely that his insane, presumed dead, Death Eater son escaped while under Winky's care and is on the loose.]]
* Rita Skeeter is first mentioned writing articles in the aftermath of the World Cup riots and goes on to become an important character.
* Percy mentions Mundungus Fletcher trying to defraud the Ministry for damages at the World Cup. He first appear and becomes important in ''Order of the Phoenix''.
* Molly buys dress robes for Harry and Ron, as they were specified on the school list. The reason turns out to be the Yule Ball.
* The Ministry responds to Mad-Eye Moody's house because he claims there was an intruder. It later turns out [[spoiler:there ''were'' intruders, Peter Pettigrew and Barty Crouch Jr., and the latter began impersonating the real Moody after they captured him.]] Diggory also mentions that Moody was supposed to be starting his new job that same day, soon revealed to be Defense Against the Dark Arts professor at Hogwarts.
* Draco Malfoy mentions Durmstrang, which becomes important later in the book, and that his father knows the headmaster. This is because [[spoiler:Lucius Malfoy and Igor Karkaroff were both Death Eaters.]]
* Hermione says that Drumstrang has a "horrible reputation" due to its association with the Dark Arts. In ''Deathly Hallows'', we learn that it also produced Gellert Grindelwald, the second worst Dark Wizard of the 20th century.
* Ron says that it's a shame that Malfoy's mother likes him. In ''Deathly Hallows'', [[spoiler:Narcissa Malfoy's love for her son ends up saving Harry's life and directly leading to Voldemort's downfall.]]
* The trio buys food from the lunch trolley. The witch pushing it has an expanded role in ''Cursed Child''.
* Malfoy remarks that Harry will probably enter the Triwizard Tournament because he likes to show off. [[spoiler:Harry ''does'' end up entering, but not by choice.]]
* The students ride to the castle in "horseless carriages." In ''Order of the Phoenix'', it is revealed they are pulled by thestrals.
* During the Sorting, Harry asks Ron and Hermione if brothers and sisters end up in the same Hogwarts house; Hermione replies no and cites the Patil twins, Padma (Ravenclaw) and Parvati (Gryffindor). Another sibling pair in different houses is revealed later: Sirius Black in Gryffindor and his brother Regulus Black in Slytherin ([[spoiler:Due to his HeelFaceTurn when replacing Voldemort's Horcrux, maybe he should have been in Gryffindor after all]]).
* Mad-Eye Moody is stated to be drinking from a flask. The fact that it contains [[spoiler:Polyjuice Potion]] is revealed at the end of the book.
* Professor Trelawney claim that the thing Harry dreads will soon come to pass. As a matter of fact, [[spoiler:Voldemort returns to power at the end of the book.]]
* Moody mentions that he's going against what the Ministry deems appropriate for the fourth year Defense Against the Dark Arts class. In ''Order of the Phoenix'', the Ministry exercises significantly more control over the curriculum when Professor Umbridge is hired.
* Moody teaches the class about the Unforgivable Curses, which are important from here on out.
* Neville's aptitude for Herbology is mentioned again. By the time of ''Cursed Child'', [[spoiler:he is the Hogwarts Herbology professor.]]
* Moody notes that Neville is the one who volunteered information about the Cruciatus Curse. We later learn that [[spoiler:Moody is actually Barty Crouch Jr., one of the Death Eaters who tortured Neville's parents into insanity with this curse.]]
* Neville is extremely bothered by the demonstration of the Cruciatus Curse because [[spoiler:his parents suffered greatly from it and are permanently mentally disabled as a result.]]
* Moody lends Neville ''Magical Water Plants of the Mediterranean''. [[spoiler:This was Barty Crouch Jr.'s attempt to invoke this trope, assuming that Harry would ask him for help with the Second Task and that Neville would tell him about gillyweed, but it is unsuccessful in the book (though it works in the film).]]
* While lying on their Divination homework, Harry "predicts" that he will be in danger of burns. [[spoiler:He ends up facing a dragon during the first task.]] Ron claims Harry will be stabbed in the back by someone he thought was a friend. Not only does [[spoiler:his friendship with Ron temporarily estranged]], but [[spoiler:Mad-Eye Moody is a Death Eater in disguise plotting to send Harry to be killed by Voldemort.]]
* Fred and George are writing something mysterious. This is later revealed to be [[spoiler:a letter to Bagman about the fact that their gambling winnings were paid in leprechaun gold.]]
* Ron twice makes up predictions that he will drown. During the second task, [[spoiler:he is submerged at the bottom of the lake for an hour.]]
* Harry proves decent at resisting the Imperius Curse. This comes in handy [[spoiler:when Voldemort places him under it during their confrontation.]]
* One of the Beauxbatons students gives a derisive laugh at Dumbledore's speech. She turns out to be Fleur Delacour, an important character.
* Dumbledore's wand becomes much more important in ''Deathly Hallows'', when it is identified as [[spoiler:the Elder Wand.]]
* Karkaroff's reaction upon seeing Moody is because [[spoiler:he was the Auror that arrested him after the fall of Voldemort.]]
* Crouch's behavior and appearance are mentioned as being slightly off. This is because [[spoiler:he's resisting the influence of his son's Imperius Curse.]]
* Moody describes in detail what someone would have needed to do in order to enter Harry in the Triwizard Tournament. [[spoiler:He knows so much because this is exactly what he did.]]
* Harry fantasizes about using the Cruciatus Curse on Snape. In ''Order of the Phoenix'', [[spoiler:he attempts it on Bellatrix Lestrange]] and, in ''Deathly Hallows'', [[spoiler:uses it successfully on Amycus Carrow.]]
* Ollivander becomes important in ''Deathly Hallows''. He also mentions Gregorovitch, who is likewise important in that book.
* Harry remembers that his wand and Voldemort's share twin cores, which becomes extremely important at the end of the book.
* Harry notices the trunk in Moody's office. This contains [[spoiler:the real Mad-Eye Moody.]]
* Trelawney says she has seen the death descending over Hogwarts in the crystal ball and looks preoccupied at Harry while saying so. [[spoiler: At the end of the year, Cedric dies in front of Harry.]]
* Winky claims that Bagman is a bad man. We later learn the reason she thinks this is because [[spoiler:he was prosecuted for unknowingly passing information to the Death Eater spy Augustus Rookwood.]]
* Ron says "Percy wouldn't recognize a joke if it danced naked in front of him wearing Dobby's tea cozy." In ''Deathly Hallows'', he actually does tell a joke [[spoiler:moments before Fred is killed by Rookwood.]]
* Harry fails a Potions test because he forgets to add a bezoar. This particular item because very important in ''Half-Blood Prince'', when [[spoiler:Ron is poisoned.]]
* Ginny suggests that Harry go to the Yule Ball with Ginny, [[spoiler:who Harry ends up marrying.]] Meanwhile, Harry asks Lavender Brown to go to the ball with Ron, and they end up dating in ''Half-Blood Prince''.
* Sirius gives Harry a magical penknife for Christmas. In ''Order of the Phoenix'', [[spoiler:he uses this to break into Umbridge's office and ends up destroying it trying to break into the Love Chamber in the Department of Mysteries.]]
* Dumbledore makes mention of once having had a full bladder and discovering a room full of chamberpots that later vanished. He theorizes that perhaps the room only appears when someone has need of it. In ''Order of the Phoenix'', [[spoiler:the Room of Requirement becomes very important.]]
* A seemingly irrelevant beetle is sometimes mentioned, starting at the Yule Ball. This turns out to be [[spoiler:Rita Skeeter, who is an unregistered Animagus.]]
* It is mentioned that the giants were driven into hiding on the European mainland, Hagrid's mother Fridwulfa among them. This becomes more important in ''Order of the Phoenix'', [[spoiler:when the Order and the Death Eaters vie for an alliance with them, and Hagrid meets his half-brother Grawp.]]
* Harry is shocked that Krum is swimming in the lake in January. We later learn that he's doing this [[spoiler:because he's training for the second task.]]
* Dumbledore says that his brother Aberforth had been convicted for practicing inappropriate harms on a goat. Aberforth first appears in ''Order of the Phoenix'', and is first identified as such in ''Deathly Hallows'', where he has an important role. He also claims to be unsure if Aberforth can read, [[spoiler:which sounds much crueler when it is revealed that Albus's genius played a large role in their estrangement.]]
* When Moody taunts Snape about spots that never come off, Snape grabs his forearm convulsively. [[spoiler:Dark Mark tattoos]] are revealed at the end of the book.
* Moody suggests that Harry try a career as an Auror. According to ''Pottermore'', [[spoiler:he does become an Auror]], and by ''Cursed Child'', [[spoiler:he has become the Head of the Department of Magical Law Enforcement.]]
* Hermione mentions the International Code of Wizarding Secrecy, which is a major plot point in the ''Fantastic Beasts'' film.
* Harry notes that the merpeople in the lake look very different from the painting of the one in the prefects' bathroom. The different races of merpeople are elaborated on the in ''Fantastic Beasts'' book.
* Snape threatens Harry with Veritaserum. This potion is used later on to [[spoiler:interrogate Barty Crouch Jr.]]
* Hermione complains about Crouch's unfair treatment of Winky and Sirius says "if you want to know what a man's like, take a good look at how he treats his inferiors, not his equals." In ''Order of the Phoenix'', [[spoiler:he treats his own house-elf Kreacher like vermin, which ends up leading to his own death.]]
* Sirius tells the trio about the late Barty Crouch Jr. It turns out that [[spoiler:not only is he still alive, he's been posing as Mad-Eye Moody for the entire book.]]
* Sirius mentions the Lestranges-Rodolphus and Bellatrix-who appear along with Rabastan later in the book via a memory. Bellatrix becomes a major character starting in ''Order of the Phoenix'', and Rodolphus has an important role in the backstory of ''Cursed Child''.
* Sirius also mentions the Death Eater Avery, who, in ''Order of the Phoenix'', [[spoiler:provides Voldemort with faulty information that results in a number of failed attempts to steal the prophecy, effectively stalling his plans for most of the book.]]
* Ron talks about Percy's ambition and Hermione claims that he would never throw his family to the dementors. In ''Order of the Phoenix'', [[spoiler:he doesn't go that far, but he does become estranged from his family members due to his Ministry career.]]
* Hagrid gives his class a lesson on nifflers. In the ''Fantastic Beasts'' film, a niffler is more important to the plot.
* Dumbledore contacts Hagrid using his Patronus. This method of communication starts becoming more important in ''Order of the Phoenix''.
* Harry jokingly suggests that Snape can turn himself into a bat. In ''Deathly Hallows'', it is revealed that [[spoiler:he can fly, and is described as looking similar to a bat.]]
* George claims that Ron's behavior may lead to him being made a prefect, which angers Ron. In ''Order of the Phoenix'', [[spoiler:he ''does'' become a prefect.]]
* Voldemort tells Nagini that she will be able to eat Harry's corpse. In ''Deathly Hallows'', [[spoiler:this is exactly how Voldemort disposes of Charity Burbage's body.]]
* Harry sees the sword of Gryffindor in Dumbledore's office. It becomes critically important in ''Deathly Hallows''.
* Dumbledore's Pensieve is much more plot-relevant in ''Half-Blood Prince''.
* Harry visits Courtroom Ten via Dumbledore's memories. He goes there in person in ''Order of the Phoenix'' [[spoiler:for his own trial.]]
* Karkaroff names Antonin Dolohov, Mulciber, Travers, and Augustus Rookwood, all of whom escape from Azkaban in ''Order of the Phoenix''. In ''Order of the Phoenix'', Rookwood is instrumental in [[spoiler:telling Voldemort how to retrieve the prophecy, which results in the death of Sirius Black]], and in ''Deathly Hallows'', [[spoiler:he kills Fred Weasley.]] In that same book, Dolohov [[spoiler:kills Remus Lupin.]]
* Dumbledore mentions that Snape became a spy, which is important for the rest of the series.
* Dumbledore also claims that Snape "is now no more a Death Eater than I am." In ''Deathly Hallows'', we learn that [[spoiler:Dumbledore once held magical supremacist beliefs and was friends in his youth with Gellert Grindelwald, whose philosophy he helped shape.]]
* It is revealed that Frank and Alice Longbottom were tortured by Death Eaters. They appear in ''Order of the Phoenix''.
* Bellatrix Lestrange demonstrates her fanatical loyalty to Voldemort and her belief that she and her companions will be rewarded. In ''Order of the Phoenix'', [[spoiler:she is proven right when all the imprisoned Death Eaters are broken out of Azkaban.]]
* Dumbledore refuses to tell Harry his reasons for trusting Snape. It is revealed in ''Deathly Hallows''.
* Fleur is described as being attracted to Bill Weasley when they are briefly in the same room. They begin dating in ''Half-Blood Prince'' and get married in ''Deathly Hallows''.
* The murder of Cedric Diggory becomes a major plot point in ''Cursed Child'', as [[spoiler:Harry's son Albus attempts to prevent it from happening to avert the Second Wizarding War]]. The fact that it happened in front of Harry allows him to see thestrals in ''Order of the Phoenix''.
* Voldemort says that he took steps "to guard myself against mortal death." We learn what these were in ''Half-Blood Prince''.
* The Death Eater Avery begs Voldemort for forgiveness. Avery winds up being very important to the plot of ''Order of the Phoenix'', as [[spoiler:his faulty information regarding the Hall of Prophecy results in the imprisonment of Sturgis Podmore, the wounding of Arthur Weasley, Dumbledore suspecting that that Nagini is a Horcrux, the death of Broderick Bode, and the stalling of Voldemort's plans for most of the book.]]
* Voldemort makes Wormtail a silver hand and tells him "may your loyalty never waver again." In ''Deathly Hallows'', [[spoiler:when he briefly wavers in his loyalty, the hand kills him.]]
* Voldemort declares that Azkaban will be "broken open," "the dementors will join us," and "we will recall the banished giants." In ''Order of the Phoenix'', [[spoiler:all of these things come to pass.]]
* Voldemort notes the absence of six Death Eaters. "Three dead in my service," two of whom have already been revealed as Evan Rosier and Wilkes, while the third, Regulus Black, is revealed in ''Order of the Phoenix''. He also says that one "too cowardly to return" will pay ([[spoiler:Igor Karkaroff, who is killed in ''Half-Blood Prince'']]), one he believes "has left me forever" ([[spoiler:Severus Snape, who returns to his side later in the book]]) and his most faithful servant "who has already reentered my service" ([[spoiler:Barty Crouch Jr., who is soon revealed to have been posing as Mad-Eye Moody all along]]).
* Dumbledore's brief look of triumph when he is told that Voldemort used Harry's blood to resurrect himself. As revealed in ''Deathly Hallows'', [[spoiler:Dumbledore just realized that Voldemort had just made it possible for Harry to survive the Killing Curse again.]]
* Dumbledore tells Harry that "no spell can reawaken the dead" and that the people he saw coming out of Voldemort's wands were merely echoes. In ''Deathly Hallows'', we learn that [[spoiler:the Resurrection Stone is capable of actually recalling people from the afterlife, but with drawbacks.]]
* Dumbledore tells Fudge that he will go down in history as one of the worst Ministers for Magic if he sticks his head in the sand and denies Voldemort's return. [[spoiler:This is exactly what ends up happening.]]
* Fudge declares that the Ministry will be looking into the running of Hogwarts from now on. In ''Order of the Phoenix'', this comes in the form of Dolores Umbridge.
* Dumbledore orders Sirius to make contact with "the old crowd," revealed in ''Order of the Phoenix'' to be, well, the Order of the Phoenix. He also mentions Arabella Figg, [[spoiler:who turns out to be the same Mrs. Figg as the one who lives in Little Whinging.]]
* Hermione makes a loud slamming noise and grips something in her hand while everyone is in the hospital wing. [[spoiler:She captured Rita Skeeter in beetle form.]]
* Amos Diggory returns in ''Cursed Child'', and still hasn't gotten over Cedric's death.
* Hagrid and Madame Maxime are preparing to carry out a mission on behalf of Dumbledore over the summer. In ''Order of the Phoenix'', we learn that [[spoiler:they are traveling to mainland Europe to make contact with the giants.]]
* Fleur mentions that she wants to get a job to improve her English. In ''Half-Blood Prince'', it is revealed that she gets hired at Gringotts.
* Harry gives his Triwizard winnings to Fred and George for the joke shop. They end up opening Weasleys' Wizard Wheezes in ''Half-Blood Prince''.
[[/folder]]

[[folder:Fantastic Beasts and Where to Find Them (book)]]
* Newt Scamander is still in the process of writing this book during the events of the film of the same name.
* Newt Scamander himself is briefly characterized in the beginning of the book, and goes on to become the main character of the film.
* Porpentina Scamander (née Goldstein) receives a single mention in the "About the Author" section. She is a major character in the film.
* Scamander cites Bathilda Bagshot, who is important in ''Deathly Hallows'', where it is revealed that [[spoiler:she is the great-aunt of Gellert Grindelwald, whom Scamander helped American Aurors briefly capture in the ''Fantastic Beasts'' film.]]
* Scamander mentions the "extremists" who want Muggles classified as beasts. Not only [[spoiler:does this essentially become official policy under the Voldemort-controlled Ministry of Magic]] in ''Deathly Hallows'', the ''Fantastic Beasts'' film reveals that Scamander himself encountered [[spoiler:Grindelwald.]]
* Scamander mentions the International Confederation of Wizards, which appears in the ''Fantastic Beasts'' film.
* Scamander refers to breaches of the International Code of Wizarding Secrecy. The ''Fantastic Beasts'' film reveals that he was involved in fixing one after [[spoiler:Grindelwald set an Obscurus loose in Manhattan.]]
* One footnote mentions the Department of Mysteries, which is very important in ''Order of the Phoenix''.
* There is an entry of Augureys. This creature's name is used as the alias of [[spoiler:Delphini]] in ''Cursed Child''.
* There is an entry on Bowtruckles. They make an appearance in the ''Fantastic Beasts'' film.
* American wizards are mentioned several times. The wizarding community of the United States has a major focus in the ''Fantastic Beasts'' film.
* There is an entry on Crups. Hagrid teaches a lesson on Crups in ''Order of the Phoenix''.
* There is an entry on Demiguises. A Demiguise under Scamander's care appears in the ''Fantastic Beasts'' film.
* There is an entry on Doxies. 12 Grimmauld Place is infested with them in ''Order of the Phoenix''.
* There is a subentry on the Ukrainian Ironbelly breed of dragon, a member of which appears in ''Deathly Hallows'' [[spoiler:chained up in Gringotts.]]
* There is an entry on Erumpents. An Erumpent horn appears in ''Deathly Hallows'' [[spoiler:where it blows up the Lovegoods' house]] and a live one appears in the ''Fantastic Beasts'' film as one of the magical creatures who escape from Newt Scamander's suitcase.
* There is an entry on ghouls. The Weasley family's ghoul becomes important in ''Deathly Hallows'', when [[spoiler:it is disguised as a Spattergroit-infected Ron.]]
* There is an entry on Knarls. Hagrid teaches a lesson on Knarls in ''Order of the Phoenix''.
* There is an entry on Nifflers. Scamander's own Niffler is prominent in the ''Fantastic Beasts'' film when it runs amok in Manhattan.
* There is an entry on Occamys, which appear in the ''Fantastic Beasts'' film. It also mentions their silvery eggs, which, in the film, [[spoiler:Scamander gives to Jacob Kowalski so he can open a bakery.]]
* There is an entry on Snidgets, which are elaborated on in ''Quidditch Through the Ages''. There is also a footnote citing that book.
* Thestrals are mentioned under the entry for winged horses, which notes that they are "black, possessed of the power of invisibility, and considered unlucky by many wizards." They make their first visible appearance in ''Order of the Phoenix'', where it is revealed that their invisibility and association with unluckiness are because [[spoiler:they can only be seen by a person who has witnessed death.]]
[[/folder]]

[[folder:Quidditch Through the Ages]]
* "T. Nott" is listed as having checked out a copy of ''Quidditch Through the Ages'' from the Hogwarts Library. He has an important role in ''Cursed Child'' [[spoiler:as the original owner of the experimental Time Turner that drives most of the plot.]]
* One of the quotes of praise for ''Quidditch Through the Ages'' is from Bathilda Bagshot, who is important in ''Deathly Hallows''.
* Kennilworthy Whisp writes that "no spell yet devised enables wizards to fly unaided in human form." In ''Deathly Hallows'', it is revealed that [[spoiler:Voldemort figured out how.]]
* The International Statute of Wizarding Secrecy is mentioned. It becomes an important plot point in the ''Fantastic Beasts'' film.
* The inventor of the Golden Snitch lived in Godric's Hollow. The town is an important location in ''Deathly Hallows'' and ''Cursed Child''.
* The wizarding community of the United States is mentioned, along with "the great intensity of anti-wizarding feeling" and "the great cauton exercised by wizard settlers." All of this becomes important in the ''Fantastic Beasts'' film.
[[/folder]]

[[folder:Harry Potter and the Order of the Phoenix]]
* Harry sees Mrs. Figg walking down the street. [[spoiler:She is soon revealed to be a Squib and a member of the Order of the Phoenix.]]
* Harry hears a noise like a gunshot and assumes that it was Dobby apparating. It turns out that it was [[spoiler:Mundungus Fletcher.]]
* It is mentioned that Harry has been having dreams about locked doors and winding passages, which are located in [[spoiler:the Department of Mysteries.]]
* Harry mentions in passing that Dudley and his gang beat up a Muggle boy named Mark Evans. Because he shares a last name with Lily Potter (née Evans) and Petunia Dursley (née), many fans assumed that he would have some importance in the future. However, this is an aversion of ChekhovsGunman, as, in the words of J.K. Rowling, "Mark Evans is... nobody. ... The car with false licence plates is at the door and I've got to glue on my goatee. Goodbye."
* The International Statute of Wizarding Secrecy is a minor plot point here and becomes much more important in the ''Fantastic Beasts'' film.
* Harry receives several official warnings from Mafalda Hopkirk. She appears in ''Deathly Hallows'' when [[spoiler:Hermione impersonates her to infiltrate the Ministry of Magic.]]
* Petunia says that she heard about dementors from "that awful boy." Harry assumes she means his father James, but ''Deathly Hallows'' reveals the boy was actually [[spoiler:Severus Snape.]]
* Petunia receives a mysterious howler commanding her to "remember my last." The sender is later revealed to be [[spoiler:Albus Dumbledore.]]
* Several members of the Order of the Phoenix first appear in the Advance Guard and then are not mentioned again until they are important to the plot. Elphias Doge is important in [[spoiler:revealing some of Dumbledore's backstory]] in ''Deathly Hallows'', Emmeline Vance [[spoiler:is murdered by Voldemort]] in ''Half-Blood Prince'', and Sturgis Podmore [[spoiler:is Imperiused by Lucius Malfoy as part of Voldemort's plot to steal the prophecy]] later in the book. Dedalus Diggle and Hestia Jones [[spoiler:protect the Dursleys]] in ''Deathly Hallows''.
* The parents of Nymphadora Tonks are mentioned several times. Ted and Andromeda Tonks appear in ''Deathly Hallows''.
* [[spoiler:The once-mentioned locket that nobody could open when Number 12 Grimmauld Place was being cleaned out, which became important in book seven]].
* A portrait at St Mungo's insists Ron must have spattergroit; Ron retorts he's just freckled. In ''[[Literature/HarryPotterAndTheDeathlyHallows Deathly Hallows]]'', [[spoiler: Ron fakes being near death with spattergroit to follow Harry on the quest for Horcruxes and buy time to avoid Death Eaters coming after his family for helping Harry]].
* The thestrals, and Harry being able to see them.
* Hermione makes a list containing the names of all the people agreeing to be in the DA. It's mentioned it that signing it feels unusually binding. [[spoiler:Hermione cursed the list so that anyone who revealed the DA to the Ministry would break out in a rash. Not just any rash, either. It (permanently, per WordOfGod) writes 'Sneak' across their face.]]
* In ''Chamber of Secrets'', a passing mention was made to Peeves breaking a cabinet, preventing Harry from getting into trouble. It's mentioned here again, when the Weasley twins push one of Umbridge's hench-students in, and he gets trapped there for months because it's magical. [[spoiler: In the next book, it's revealed to be linked with another cabinet outside the school, and Draco fixes it to let the Death Eaters in.]]
* "Snape's Worst Memory". It involves Snape being publicly humiliated by Sirius, James and Peter, and provides an interesting AlternativeCharacterInterpretation to James Potter (JerkJock, specifically). It's pretty bad on the surface... [[spoiler:but in Book 7, we learn why it was his ''worst'' memory: it was the day he lost Lily forever (due to his own behavior, not really anything James did).]]
** To a lesser extent, in that memory, Snape uses a curse on James that opens a gash on his face. [[spoiler: There's a very good chance that this was an early form of [[WoundThatWillNotHeal Sectumsempra]].]]
* ChekhovsGift: Near the middle of the book, Sirius gives Harry a magic mirror [[spoiler:which is part of a pair that can enable the two holders to communicate magically. Sirius has the other one.]] Made horrifying when you realize that the driving point of the climax of the book is that [[spoiler:Harry is trying to communicate with Sirius, but can't find a means to; only after Sirius has been murdered does he find the mirror in his school trunk.]] It's thrown away and broken, [[spoiler:but a fragment of it becomes important in ''Deathly Hallows'']].
* ChekhovsGunman:
** The barman of the Hog's Head Tavern, identified two books later as [[spoiler:Albus Dumbledore's younger brother Aberforth, who had been mentioned in passing by Dumbledore earlier]]. It was even noted that he "looked vaguely familiar"; this was because Harry had ''already seen him before'', in the photograph of the original Order Of The Phoenix that Moody showed Harry during dinner at Number Twelve, Grimmauld Place.
** Regulus Black, Sirius's brother who is mentioned in passing and the becomes important to the plot in Book 7.
** Kreacher, a seemingly minor character who, in true JK Rowling style, ends up being important to both this book's plot and that of Deathly Hallows. [[spoiler:When screenwriter Michael Goldenberg suggested writing him out of the movie adaptation, Rowling admitted, "If you do that, adapting Seven's going to be ''really'' difficult..."]]
** [[FortuneTeller Professor Trelawney]]. In [[Literature/HarryPotterAndThePrisonerofAzkaban Book 3]] Dumbledore casually mentions that he should give her a raise, since the prediction she made about [[spoiler: Wormtail]] turned out to be true, and that it was the second accurate prediction she had ever made. At the end, it's revealed what the first one was.
** This is also the book where we start to see Neville's emerging combat skill, along with his determination, both of which become of great importance in ''Deathly Hallows''.
* ChekhovsSkill: Occlumency. [[spoiler:Harry never masters it, but Snape's talent in it is vital to his role as a spy.]]
* ''The Quibbler'', and the fact that Luna Lovegood's father is the editor. We meet him in Book 7.
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[[folder:Harry Potter and the Half-Blood Prince]]
* When Harry [[spoiler:hides his potions book in the Room of Requirement]] he marked the spot with a bust of a warlock wearing a wig and [[spoiler:an old, battered tiara. Said tiara becomes immensely important in Book 7 when it's revealed to be the Lost Diadem of Ravenclaw, one of Voldemort's Horcruxes.]]
** To add to that, the [[spoiler:Room of Requirement itself. Draco was using it, specifically the Room of Hidden Things, to try and find a way to kill Dumbledore. The room is revealed in Book 7 to be the location of one of the Horcruxes, and Draco comes close to foiling Harry there because of how much experience he has with that room - as he says, "I virtually lived in the Room of Hidden Things last year." He knows how to get in.]]
* Peruvian Instant Darkness Powder. [[spoiler:Fred and George show it to Harry when he and the other Weasleys visit their joke shop in Diagon Alley, and mention how it could come in handy if one needs to make a quick escape. Come the end of the book where the school is infiltrated by Death Eaters thanks to Malfoy, and it does exactly that.]]
* Tonks' Patronus changing its form. The fact that it's supposed to represent [[spoiler:Lupin shows that the Patronus often represents someone the caster loves... much like Snape's.]]
* During this years' only Hogsmeade trip, the trio encounter Mundugus again, [[spoiler:selling things he stole from Grimmauld Place. The Hog's Head barman (Aberforth) was talking to him as they approached, and most likely acquired Sirius' mirror at that time, which becomes quite significant in the next book.]]
* Romilda's love potions. [[spoiler:Ron takes them on his birthday, and he falls in love with her, so naturally, Harry takes Ron to Professor Slughorn for a cure, but Prof. Slughorn ends up giving him poison....]]
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[[folder:Harry Potter and the Deathly Hallows]]
* [[spoiler:Harry's snitch, Dumbledore's Deluminator (aka the Put-Outer), Godric Gryffndor's [[SwordOfPlotAdvancement sword]], dragons at Gringotts, the poem [[TooDumbToLive warning thieves at Gringotts]] entrance, the eye Harry sees in Sirius's mirror, the tiara Harry put on a bust to mark a spot in the Room of Requirement, the locket in the House of Black, Wormtail's hand, Voldemort's claim about Wormtail's loyalty, Wormtail's debt to Harry, Harry's invisibility cloak, and the Basilisk's fangs.]]
** Not to mention [[spoiler:the protection charm cast by Lily which protect Harry from Voldemort. Harry's HeroicSacrifice fuels the same charm, protecting ''all the students and staff of Hogwarts''.]]
* ChekhovsGunman: Kreacher, Dobby, Aberforth, Grindelwald, Gregorovitch.
* ChekhovsGag: Movie-only. In the movies, Seamus had a RunningGag where he'd blow things up accidentally (usually in the [[FunnyBackgroundEvent background]]). Come the Battle of Hogwarts [[spoiler: and [=McGonagall=] knows exactly who to turn to for the demolition of the Hogwarts bridge.]]
** Trelawney's [[spoiler: continued obsession with Harry's death]] finally comes to fruition in this book, though it's the one year where they don't interact until the very end [[spoiler: and [[NotQuiteDead it doesn't take]] anyway]].
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[[folder:The Tales of Beedle the Bard]]
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[[folder:Harry Potter and the Cursed Child]]
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[[folder:Fantastic Beasts and Where to Find Them (film)]]
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