An Older Than Print meta-example—and perhaps the Ur-Example—appears in the legendary Arabian Nights. This collection of tales has a Framing Device—King Shahryar discovers that his sister-in-law has cheated on his brother, and then learns that his own wife is unfaithful, too. Shahryar is so furious that he decides all women must be executed, and he demands that a new virgin girl be delivered to him every night so that he can enjoy her company, then behead her in the morning. Eventually, the virgin supply runs dangerously low, so Shahryar's vizier is forced to present his own daughter, Scheherazade, an exceptionally well-read woman. Scheherazade asks for one final request: that she can say goodbye to her sister Dunyazade. While the two women are together, Dunyazade asks her older sister to tell her a story (a plan which the pair made in advance). Scheherazade agrees and begins to tell an amazing tale, knowing that King Shahryar is in earshot. She reaches a particularly exciting point in the narrative...then stops, explaining that the dawn has come and therefore it's time for her to die. The king can't bear the thought of not hearing the ending, so he decides to delay the execution for one more day. That night, Scheherazade indeed finishes the story...then starts telling another one, even more thrilling than the last, and again stopping at the juiciest bit. Sure enough, King Shahryar decides to spare her that night, too—and one thousand and one nights later, he's fallen so in love with her that he makes her his queen and stops killing altogether.
One must really feel sorry for those who read the Alex Rider novel Scorpia before Ark Angel came out. The novel ends with Alex being shot in the chest and him seeing his dead parents which gives the assumption that the bullet killed him. Even though he was proved to have survived with the release of Ark Angel, some fans still think that he was killed in Scorpia and have varying theories about the later books.
Demonglass ends with Abby Thorne being burnt to the ground while under attack from the Eye with Archer and Sophie's Dad still trapped inside Cal running in to try and find them, Sophie's powers blocked, Jenna missing, possibly dead and Sophie being told that she could find her mother with supposed evil prodigium hunter Aislinn Brannick. Also Demonfied Nick is loose and killed nearly 20 people in one night, Demonfied Daisy was also released, we still do not know what happened to Chaston, Anna, or the other missing students, half the Council was killed and the good guys were actually the bad guys, so the bad guys might be the good guys, but were not sure yet.
Edgar Rice Burroughs's The Gods of Mars ended with Dejah Thoris, Thuvia, and Phaidor all trapped in the Temple of the Sun for a year — and with Phaidor trying to stab Dejah Thoris. John Carter has to live out that year in ignorance.
Lloyd Alexander's The Remarkable Journey of Prince Jen ends every chapter except the side stories and the finale with one of these, along with an italicized paragraph directly addressing the reader and asking questions in the vein of "What will happen next?"
Lampshaded in The Pendragon Adventure by Pendragon. Since most of the series takes place as a series of his journals, which he frequently writes before falling asleep, he has once written about an impending catastrophe... only to apologize in the next journal, saying he couldn't stay awake to continue.
Bruce Coville's The Song of the Wanderer ends with the big bad getting the key that will allow her to destroy Luster, cue huge build up and a to be continued. The sequel about the epic war is then put on hiatus and not published until nearly 10 years later.
The Tennis Shoe Adventure books start being cliffhangers after book 2, and they haven't stopped. Last time we checked, the fate of every. Single. Character. Was hanging in the hands of a cocky 19-year-old and time was running out. And this was in...what, 2006?
In the Sammy Keyes series, Wendelin Van Draanen loves ending every single one of her chapters with a cliffhanger. (Thankfully, they're always resolved with a turn of the page. Face it, as annoying as this can get, you can't say as much for the cliffhangers of otherauthors.)
Chronicles Of Nick ends everybook with some new cliffhanger. Sherrilyn Kenyon loves to make fans crave the next book to find out what happens.
Harry Potter and the Goblet of Fire ended with Harry finishing his fourth year at Hogwarts. Oh, and the little incidental fact that Voldemort had returned, meaning that everything was about to change for the heroes and the world in which they lived. Naturally, the fandom exploded with theories, Wild Mass Guessing, and more Fan Fic than anyone could reasonably hope to read. The next book, Order of the Phoenix, wasn't published until three years later, prompting many fans to dub the interval "the three-year summer."
Order of the Phoenix, Half-Blood Prince, and, to a lesser extent, Prisoner of Azkaban end on cliffhangers as well. The first book also has a minor Sequel Hook with Dumbledore's mention that there are still other ways Voldemort could return, although that thread doesn't pay off until the fourth book. Goblet Of Fire, however, goes so far as to title its final chapter "The Beginning".
Also, in Harry Potter and the Philosopher's Stone, if you were reading one chapter at a time, you were definitely on the edge of your seat with the words at the end of Through the Trapdoor: " But it wasn't Snape. It wasn't even Voldemort."
Six Sacred Stones takes the concept of a cliff hanger one epic step further. The novel ends with Jack West falling into an abyss, without his maghook.
Every chapter of every Goosebumps book ends in this manner, which leads the reader to wonder what happens next, ESPECIALLY at the end of the book.
The Princess Bride (novel) ends with a Bolivian Army Ending, with everyone separated, stuck, and surrounded by enemies. We get Cop Out in the preview for the sequel, where somehow the crew of Dread Pirate Robert's ship comes in at the last moment and saves them. Also, Goldman writes about how Morgenstern (the "original" author) had a monetary stake in trees at the time, so to get people to care more about trees, he decided to spend 95% of the chapter talking about how great trees are, with details of their rescue sparsely peppered in, so you'd need to read about the trees just to read the cop out.
The Dresden Files: Changes ends with Harry shot dead, yet the series is obviously not concluded.
In the Heroes of Olympus series, the third book (The Mark of Athena) ends with Percy and Annabeth falling into Tartarus and hey, the first and second book ended with cliffhangers too, but this one tops them both.
Knee-Deep in the Dead: Fly and Arlene are trapped on Deimos, Earth is being invaded, and their air supply is running out. But Arlene has a plan to get them to Earth.
Hell on Earth: Fly and Arlene are trapped on the 40th floor of the Disney building, enemies pounding at the door, and Jill and Albert flying for Hawaii. But Arlene has a plan to get them down and to Hawaii; involving duct tape, computer wiring, and "the biggest goddamn boot" he can find.
Infernal Sky: Fly and Arlene are trapped on board the Fred ship with no way to alter its course and heading for the Fred homeworld. But Arlene hates Fly for going too far and taking them centuries away from their war and her husband.
In Michael Flynn's Spiral Arm series, Up Jim River ends with Donovan buying a ticket to visit his daughter and her mother, and being caught there. In the Lion's Mouth ends with Mearana vanishing with Ravn, and Bridget, knowing it was done to lure her, nevertheless says she must follow.
Most of The Black Company novels tie up fairly well and have a Time Skip between them. The exception is Shadow Games, ending with the Company in shambles, Lady unaccounted for, and Croaker captured by a mysterious Sorceror and presumed dead by his men. The following book, Dreams of Steel, picks up right where Shadow Games left off, though from a different character's perspective.
In the Horatio Hornblower series, Ship of the Line ends with Horatio forced to surrender his destroyed ship to the French while Bush has had his foot shot off. The next book, Flying Colours, is about their escape from France back to England.
Anthony Horowitz must have really wanted to piss his readers off when he was planning out Necropolis , the fourth book of The Power of Five series, where in the end Scarlett gets shot and it is revealed to the reader that all five gatekeepers, who need to stay together in order to defeat the Old Ones, are going to be separated by even greater distances than before.
What made it worse was that we had to wait four years for Oblivion.
The Rainbow Magic series sometimes have these. The Weather Fairy books ended with Doodle telling the girls something; the more books that went on the more he said.
Sophie the Sapphire Fairy's book ended with the fairies' flying magic beginning to fade.
Wildbow, the author of Pact and Worm, is especially fond of these - he subscribes to the belief that continued tension is necessary to keep readers following his work, which is published in serial format, so he will more often than not end a chapter on a cliffhanger of some sort, including the introduction of a new enemy, a sudden turn of fortunes for the protagonists, or when all else fails, mysterious hinting at an Unspoken Plan Guarantee. He has, on occasion, ended a chapter mid-sentence.
The Reynard Cycle: At least half of the chapters (if not more) of this series end this way.
Insurgent ends with an epic one, with the revelation that Chicago was walled off as part of an experiment to restore humanity to a war-torn world, and that once there are enough Divergent people among them then they should open the gates and re-enter the wider world.
In the Star Darlings franchise, the second book ends with the girls learning that one of them isn't actually a Star Darling. This plot point is picked up on and resolved in later books.
Thomas Hardy's 1873 novel A Pair of Blue Eyes features a literal cliffhanger ending in Chapter XXI that is sometimes credited as the Trope Namer; Henry Knight has slipped over the edge of a cliff when he and Elfride Swancourt are the only people for miles around, and is left hanging on for dear life as Elfride runs to get help before he loses his grip. In the next chapter, Elfride returns, fashions a rope from her undergarments, and is able to pull Knight to safety.
Most of the H.I.V.E. Series end in this. Particularly Aftershock. Mark Walden deserves an award.
Ryan Graff's The Fires of Affliction, the first book of a trilogy in progress, ends with the villain on the loose, war on the horizon, and the protagonist Khan Eilon willingly trapped in a dream of his ideal life.
1920s movie director Frank Capra, in his autobiography "The Name Above the Title" (which is now discredited for its many self-serving lies and distortions), describes in detail a scene from his film "Tramp Tramp Tramp" in which actor Harry Langdon is stuck on a fence above a sheer cliff as the fence begins to collapse. Capra's description builds to the climax of this scene but then refuses to tell us how Langdon escapes, with Capra justifying the omission by reminding us that this scene is "a cliffhanger". But it's only a true cliffhanger if Capra was planning to tell us the answer in his next book. (He wasn't.) This evasion is doubly dishonest because it covers a dishonesty in the original movie: when the fence collapses over the cliff, the cliff magically changes into a steep hill, and Langdon rides the fence's planks downhill to the bottom.
The end of Salvation's Reach, a Gaunt's Ghosts novel, reveals that Tarmaggedon Monstrum Rex, the powerful demon ship which had fled the space battle described earlier, managed to find the spaceship carrying the Ghosts and now is again pursuing them.