%% ZeroContextExample entries are not allowed on wiki pages. All such entries have been commented out. Add context to the entries before uncommenting them.


->'''Donna:''' Agatha, people love your books, they really do, they're gonna be reading them for years to come.\\
'''Agatha:''' If only! Try as I might it's hardly great literature, now that's beyond me. [[ItWillNeverCatchOn I'm afraid my books will be forgotten]], like [[http://en.wikipedia.org/wiki/Ephemera ephemera.]]
-->-- ''Series/DoctorWho'', [[Recap/DoctorWhoS30E7TheUnicornAndTheWasp "The Unicorn and the Wasp"]]

[[UsefulNotes/KnightFever Dame]] Agatha Mary Clarissa Christie (15 September 1890 12 January 1976) was the Queen of English MysteryFiction, ranked with Creator/ArthurConanDoyle as the greatest mystery writer of all time. Her stories are elaborately plotted puzzle pieces, full of false identities and faked deaths. She enjoyed a very long career; her first novel, ''The Mysterious Affair at Styles'', was published in 1920, while her final novel, ''Sleeping Murder'', was published posthumously in 1976. Among the best-selling authors of all time[[note]]The ''[[Literature/GuinnessWorldRecords Guinness Book]]'' says she's sold more books than any other individual author. If you count shorter works, Creator/WilliamShakespeare takes the lead. If corporations are invited, the collected works of Creator/WaltDisney Productions top the list. Regardless, she's sold three billion copies in over 100 languages[[/note]].

Her principal detectives were:

* ''Literature/HerculePoirot'', a retired Belgian police detective turned P.I. Fastidiously neat, he pretended to be a FunnyForeigner in order to put his clients and suspects off their guard. Agatha Christie herself eventually tired of the character, but since fans enjoyed him, she continued to write Poirot stories. He appeared in 33 novels and 51 short stories.
* ''[[Literature/MissMarple Miss Jane Marple]]''. Seemingly a fluffy old spinster, her mind was as sharp as her knitting needles; having lived in small towns her whole life, nothing about human nature ever surprised her. She appeared in 12 novels and 20 short stories.
* ''Literature/TommyAndTuppence Beresford'', a husband and wife team. Their adventures were more like spy novels than straight mysteries, though they did contain elements of classic detective novels. They appeared in five books: four novels and a short story collection, ''Partners in Crime''.

Christie also wrote 16 novels which did not feature any of her series detectives. These ranged from traditional mysteries with one-shot detectives to {{Thriller}}s which placed more emphasis on action than detection. The latter were almost universally the most poorly received of Christie's works, while one of the former, ''Literature/AndThenThereWereNone'', is widely regarded as one of her best, even ''the'' best. Six of her novels, which are usually classed as {{Romance}}s, were written under the pseudonym Mary Wesmacott.

While most of the stories are nominally set in the year of publication, in practice they all take place in the time of the GenteelInterbellumSetting. Of Christie's series detectives, only the Beresfords age in real time. Poirot and Marple both begin as elderly characters and over the course of Christie's 56-year career, age roughly 20 years at most. (This matches a line from the final Poirot novel ''{{Literature/Curtain}}'', in which it is stated that it has been "over twenty years" since the first adventure, ''Literature/TheMysteriousAffairAtStyles'', which came out in 1920 and was set during World War 1.)

Christie possessed an uncanny ability to subvert the reader's expectations. Being well aware of the mystery conventions of the time, she was frequently able to subvert them for a TwistEnding. For example, Christie knew that there were certain characters, who by virtue of their role in the story, the reader would not suspect. To drive home the point that [[EveryoneIsASuspect the reader should suspect]] ''[[EveryoneIsASuspect everybody]]'', she would frequently make one of these characters the murderer.


* The ''way'' too obvious suspect ([[TheUntwist who therefore of course won't turn out to be the real killer, now will they?]][[invoked]]) really ''was'' the killer after all.
* [[EverybodyDidIt everyone was guilty]].
* [[NarratorAllAlong the narrator was guilty]].
* [[DetectiveMole one of the sleuths investigating the mystery was guilty]].
** the guilty party was impersonating the detective.
* one of the murder victims was guilty.
* the murders looked like the work of an AxCrazy killer, but the murderer was not crazy.
* the initial victim was a distraction, and the major intended victim was one of those killed later.
* there was no murderer at all.
* the murder took place in the narrator's head only.
* the SecretCircleOfSecrets are the ''good'' guys.


She ''invented'' most of the above twist endings. For a list of her works, [[Bibliography/AgathaChristie see this page.]]

Most of the books in the main series have been televised, and many filmed, some repeatedly. There's even an ''{{anime}}'' {{Crossover}} of [[Anime/AgathaChristiesGreatDetectivesPoirotAndMarple Poirot and Miss Marple]].

!!Christie works which have their own pages:
* Literature/HerculePoirot series
** ''Literature/TheMysteriousAffairAtStyles'' (1920)
** ''Literature/TheMurderOnTheLinks'' (1923)
** ''Literature/TheMurderOfRogerAckroyd'' (1926)
** ''Literature/TheBigFour'' (1927)
** ''Literature/TheMysteryOfTheBlueTrain'' (1928)
** ''Literature/PerilAtEndHouse'' (1932)
** ''Literature/LordEdgwareDies'' (1933)
** ''Literature/ThreeActTragedy'' (1934)
** ''Literature/MurderOnTheOrientExpress'' (1934)
** ''Literature/MurderInMesopotamia'' (1936)
** ''Literature/TheABCMurders'' (1936)
** ''Literature/CardsOnTheTable'' (1936)
** ''Literature/DeathOnTheNile'' (1937)
** ''Literature/OneTwoBuckleMyShoe'' (1940)
** ''Literature/SadCypress'' (1940)
** ''Literature/EvilUnderTheSun'' (1941)
** ''Literature/FiveLittlePigs'' (1942)
** ''Literature/CatAmongThePigeons'' (1959)
** ''Literature/TheClocks'' (1964)
** ''{{Literature/Curtain}}'' (1975)
* Literature/TommyAndTuppence series (1922)
* ''Literature/TheMysteriousMrQuin'' (1930)
* Literature/MissMarple series
** ''Literature/TheMurderAtTheVicarage'' (1930)
** ''Literature/TheBodyInTheLibrary'' (1942)
** ''Literature/TheMovingFinger'' (1943)
** ''Literature/AMurderIsAnnounced'' (1950)
** ''Literature/TheMirrorCrackdFromSideToSide'' (1962)
* ''Literature/ParkerPyneInvestigates'' (1934)
* ''Literature/AndThenThereWereNone'' (1939)
* ''Literature/DeathComesAsTheEnd'' (1944)
* ''Literature/TowardsZero'' (1944)
* ''Theatre/TheMousetrap'' (1952)

[[folder:Associated Tropes:]]
* AdaptationNameChange[=/=]CompositeCharacter: In the play rendition of ''Death on the Nile'' known as ''Murder on the Nile'', there are significantly fewer characters than in the book counterpart. Names of some characters have also been changed:
** Marie Van Schuyler and Mrs. Allerton merge into the character Helen ffoliot-ffoulkes.
** Miss Bowers and Cornelia Robson merge into the character Christina Grant.
** Mr. Fanthrop and Mr. Ferguson merge into the character William Smith.
** Hercule Poirot, Colonel Race, and Andrew Pennington merge into the character Canon Ambrose Pennefather.
** Simon Doyle's name changes to Simon Mostyn.
** Linnet Ridgeway's name changes to Kay Ridgeway.
** Jacqueline de Bellefort's name changes to Jacqueline de Severac.
** Louise's name isn't changed although her last name is never mentioned.
** Characters taken out completely include:
*** Salome and Rosalie Otterbourne
*** Tim Allerton
*** Fleetwood
*** Joanna Sutherwood
*** Lord Windelsham
* ADayInTheLimelight: After a number of minor, supporting, and cameo roles, Superintendent Battle gets to be main detective in ''Towards Zero''.
* AdjectiveAnimalAlehouse: The titular Pale Horse in ''The Pale Horse''.
* AmateurSleuth: It would be quicker to list the Christie protagonists who ''aren't'' amateurs: Literature/HerculePoirot (a private detective) and Superintendent Battle (a police detective).
%%* AmbitionIsEvil: Turns up in several Christie works.
%%* AnyoneCanDie: And in some cases, ''[[KillEmAll everyone]]''
%%* {{Arcadia}}: Often deconstructed.
%%* AssholeVictim: On multiple occasions; see the pages for individual works for details.
* AuthorAppeal: Christie's second husband was an archaeologist, and Christie eventually developed a strong interest in the subject herself. Not surprisingly, several of her mid-period novels reflect this interest either by taking place at an archaeological dig (''Murder in Mesopotamia'') or by simply having such a setting as the background (''Appointment with Death''). This interest eventually led Christie to actually set one novel in ancient Egypt itself (''Literature/DeathComesAsTheEnd'').
* AuthorFilibuster: Christie novels tended to have long StartToCorpse times, something which she was occasionally criticized for. She used the first chapter of ''Towards Zero'' to respond to these criticisms by having a character deliver a lengthy speech on how a murder is the culmination of a murderer's plot rather than the instigating point, and thus should come as late in the book as possible.
%%* BewareTheNiceOnes: Where to begin?
%%* BewareTheQuietOnes: Likewise.
%%* BigScrewedUpFamily: ''Crooked House'' and ''Literature/DeathComesAsTheEnd'', among others.
%%* BitterAlmonds
%%* {{Blackmail}}: Often the quickest way to become the next corpse.
%%* BlackSheep: sometimes appears in BigScrewedUpFamily situations.
%%** ''Literature/DeathComesAsTheEnd'': Sobek, the second son, is a hard-drinking womanizer who wastes money on expensive dancing girls.
* TheButlerDidIt: Several times, in different variations, both straight and skewed (for instance: the butler did it, but he wasn't really a butler).
* CannotSpitItOut : If the "secondary victim" was not a blackmailer, it was usually TheDitz (typically low-class and female), who knew something but was too dumb to understand what they knew. They would usually only hint to protagonists and then get murdered when the hints got to the murderer.
** Nicely subverted in one book, where a dumb parlourmaid lives to tell what she knows, but another person who didn't know anything and bluffed [[MakesSenseInContext is killed.]]
* CanonWelding: Christie's main detectives never crossed over, but several minor characters did, effectively tying the majority of her detective fiction into the same universe. See the article on this trope for more information.
** In tapes found by the family in 2008, Christie mentions that she deliberately never wanted Poirot and Marple to meet as she thought they would not get along. Christie thought Poirot would fight with Marple because he would not want an old lady telling him what to do. On the other hand, because she said it was a possibility, Poirot and Marple both exist in the same universe with each other, they just never meet.
* CerebusRollercoaster: Christie wrote her most serious and psychological works (like ''Literature/FiveLittlePigs'') in the middle of her career, in the 1940s. Her earlier and later stories, are, in general, more lighthearted.
%%* ClosedCircle: Multiple examples, described on their respective works pages.
%%* CluelessMystery: How the clues go together is usually made impossible for the reader to divine until the detective states it.
%%** Although the clues ''themselves'' will pretty much always point to the right person. The thing left out is usually details in their motivation.
* CompleteTheQuoteTitle: ''The Pale Horse'' has a DoubleMeaningTitle. Most obviously, "The Pale Horse" is the name of an old inn that is central to the plot. But, also, it is an allusion to the Literature/BookOfRevelation: "I looked, and there before me was a pale horse! Its rider was named Death." [[spoiler: In the book, three old women claim to be able to kill people using magic, and they have the body count to back up their claim.]]
%%* ConnectTheDeaths: Frequently used as a RedHerring; at least three novels feature murderers setting up a false pattern to conceal the true motive behind the crime.
* CoversAlwaysLie: Subverted. Christie was greatly displeased with the original artwork for the cover of ''The Man in the Brown Suit''; she felt it was both horribly done and intentionally misleading. From then on, all covers of the original editions required her final approval.
* DispenseWithThePleasantries: Inverted in ''The Pale Horse'' where [[AmoralAttorney Mr. Bradley]] is shocked at Mark Easterbrook dispensing with the pleasantries.
* TheDogWasTheMastermind: In ''Crooked House'', the murderer turns out to be [[spoiler:the ten year old girl who was going around playing detective]].
%%* DrivenToSuicide: Multiple variations. See the trope page for a list.
%%* TheDutifulSon: sometimes appears in BigScrewedUpFamily situations.
%%** Yahmose, the eldest son in ''Literature/DeathComesAsTheEnd''.
* {{Eagleland}}: As an rather old-fashioned British subject, it should be no surprise that her depictions of Americans in her works were just a little... off. In fact, you pick up early on that if one of her characters is American, Canadian or Australian, or is an British subject who spent any significant time there, that person is either a) the AssholeVictim, b) the killer or c) if not the killer, then a weak criminal type anyways. And of course, there's the case where everyone has ties to America; [[EverybodyDidIt they all can't have done it, right?]]
** However, being Agatha Christie, that didn't stop her from averting and subverting this trope. In "Sparkling Cyanide", for example, [[spoiler:the supposed untrustworthy American character turns out to be a double-agent spy on the side of good, and he also ends up being the one to solve the mystery and prevent the murderer from striking again. The same novel has an example of a British subject masquerading as one of those 'weak criminal type' Americans. He does this in order to slip under the radar of the British detectives - and the radar of any readers too familiar with Christie's other works.]]
%%* EnfantTerrible: [[spoiler:Josephine Leonides in ''Crooked House'']].
* EveryoneIsASuspect: One of the central tenets of Christie's body of work. In most of her books, it truly feels that ''any'' of the characters could be guilty. Surprisingly - and yet totally believably - subverted in [[spoiler: Literature/PerilAtEndHouse, Poirot making the seemingly complete list of suspects and the main culprit not being there at all despite being well-known by everybody for all the time.]]
%%* EverybodyDidIt: She wrote the Trope Maker for ''this'' one too.
* {{Expy}}:
** After noting how much she enjoyed writing the gossipy spinster Caroline Sheppard in ''The Murder of Roger Ackroyd'', Christie decided to revamp this character into someone who would become a fixture in her work -- Miss Jane Marple.
** Bobby Jones and Frankie Derwent of ''Why Didn't They Ask Evans?'' are expies of Tommy and Tuppence. The ITV productions {{lampshade|Hanging}}d this by having both sets of characters played by the same two actors.
** AuthorAvatar Ariadne Oliver's most popular character, Sven Hjerson, is a thinly-disguised expy of Poirot.
** It is outright stated in ''Sparkling Cyanide'' that Inspector Kemp is basically a less competent version of Battle. Kemp used to work under the former Superintendent and has adopted many of his mannerism.
* FakeAssistedSuicide: In ''Destination Unknown'', a secret agent recruits a suicidal young woman, telling her that if she's decided to die, she might as well make herself useful to her country, and promising that at the end of the mission, he'll help her with it. Naturally, at the end she's found happiness with another agent and has no intention of killing herself -- just as her recruiter intended.
* FateDrivesUsTogether: William Smith and Christina Grant in ''Murder on the Nile'' where he continuously courts her and at last asks to marry her. She refuses at first but it is hinted and later revealed that they do get married.
* FramingTheGuiltyParty: Multiple instances, described on their respective pages.
** In ''Towards Zero'', it becomes apparent quite early on that [[spoiler:Nevile Strange]] is being framed for the murder of Lady Tressilian. However, [[spoiler:Strange]] is actually the killer, and the false clues were planted by [[spoiler:himself]] [[BatmanGambit to make it appear that]] [[spoiler:his ex-wife was the killer and was trying to frame him]].
* GenreSavvy: Take a shot every time someone compares the current situation to a mystery novel, or even rules out a possibility based on its likelihood in fiction.
* GolfClubbing:
** A golf club is the murder weapon in ''Spider's Web''.
** Subverted in ''Towards Zero''. [[spoiler:It appears that Lady Tressilian was killed with a golf club, but the murder weapon was actually a modified tennis racket. This is important because it means that she was killed not by Audrey Strange, a left-handed golfer, but Nevile Strange, a right-handed tennis player using a backhand.]]
* GreedyJew: Distressingly, Christie often relied on the pre-War stereotypes of Jews as somehow "other" in her stories and novels, though she rarely goes into the truly offensive territory. After WW II Christie went back and edited the most offensive language out of her earlier books.
* HappilyFailedSuicide: [=MacWhirter=] in ''Towards Zero''.
* HeKnowsTooMuch: The surest way for an Agatha Christie character to sign his own death warrant is by attempting to blackmail a killer. Also goes for anyone who didn't know that they knew anything significant, or who didn't know the whole story but knew something vital. Basically, if you're in an Agatha Christie novel, you'd better hope and pray that you either don't have a major part, don't find anything out, aren't confided to by anyone; or if you do find something out, you know how to ''keep your mouth shut''. (See series and works pages for specific examples.)
%%* HeroicWannabe: William Smith in ''Murder on the Nile'' (''Death on the Nile'' play counterpart), constantly trying to win the heart of Christina Grant.
%%* HotGuysAreBastards : very, very much. The more attractive a man is, the more his appearance departs from the stuffy, military-ish rough and conservative Englishman, the more immoral he is. Attractive men will be suspected immediately, will usually remind the detectives of other handsome killers they've met, and if they're not the killers, they are likely to be accomplices, blackmailers or withholding evidence because they've acquired it while doing something immoral. Plus, with just a few exceptions, any affection of a handsome man for a woman is false, usually motivated by money.
%%** Possibly a case of WriteWhoYouKnow. Christie's first husband was a man like this; the marriage ended very badly.
* InvisibleWriting: Two short stories (one featuring Hercule Poirot and one Miss Marple), involve rich eccentrics writing their {{will}} in Invisible Ink, and challenging the heirs to find it.
* LateArrivalSpoiler: Christie's novels occasionally revealed the solutions of previous works, a habit which vexed her publishers. See the Literature/HerculePoirot page for several examples.
** One of the characters in ''The Pale Horse'' is one of the suspects from ''Literature/CardsOnTheTable''. If you read the former first, you'll know he can't be the guilty party in the latter. Which wouldn't be such a big deal if it weren't for the fact that ''Literature/CardsOnTheTable'' was a subversion of EveryoneIsASuspect where four, and only four, suspects could've committed the murder (and the murderer is one of the four). If you read ''The Pale Horse'' first, then you only have three suspects.
*** Also catches you out if you only watch the ITV film of ''Literature/CardsOnTheTable'' and don't read the book, as the relationships end up somewhat different (too long to explain here, but suffice to make this look like CanonDiscontinuity.)
** In turn, ''Literature/CardsOnTheTable'' reveals the solution to [[spoiler:Literature/MurderOnTheOrientExpress]], although mercifully not by name.
* LoveAtFirstSight: Many of the romantic developments in Christie's stories develop very rapidly when two people meet and is immediately consumed by passion for each other.
** In ''The Man In Brown Suit'', Anne rescues a young man and becomes so infatuated with him that she's willing to "walk across Africa" for his sake.
** In ''The Clocks'', Sheila Webb runs into Colin Lamb, and the latter immediately declares her as "his" girl.
* LoveHurts: A trope that became a favourite of Agatha's after her divorce from her first husband. When love wasn't driving a character to [[LoveMakesYouEvil commit murder]], it was guaranteed a broken heart from one side or the other. Only a few pairings survived amidst the body counts and broken hearts.
%%* LoveMakesYouEvil: ''Oy.'' To list all examples would be ludicrous.
%%* LukeIAmYourFather: Turns up quite a lot, usually to provide a motive.
%%* MarySue: InUniverse, several short stories have the main characters compare themselves to the iron-jawed supermen/wish they could have the beautiful heroines of the cheap novels they read. At the end, they recognize them for the fantasies that they are, and live happier lives for it.
%%** In the title character of ''The Manhood of Edward Robinson'' thoroughly enjoys his brush with high life but the main result of his adventure is that he finally asserts himself in his relationship with his fiancee - which she finds totally hot.
* TheMatchmaker: Both Hercule Poirot and Miss Marple display a tendency at times to play matchmaker in the lives of two lovers who need to be brought together during their investigations.
%%* MetaTwist
* MurderByMistake:
** In ''Sparkling Cyanide''. [[spoiler: Victor Drake]] intended to poison his cousin Iris to gain control of her fortune, but Iris's brother-in-law George ended up drinking from her glass instead of his own.
** A variation occurs in ''Curtain''. [[spoiler:Barbara Franklin]] attempts to poison [[spoiler:her husband, Dr. Franklin]], but Hastings accidentally changed the arrangement of the coffee cups by turning the table aside, causing [[spoiler:[[HoistByHisOwnPetard Barbara herself to drink the poisoned coffee]]]].
%%* MurderSuicide: A common resolution.
%%* NeverFoundTheBody
%%* RedRightHand: [[spoiler:Josephine Leonides' general appearance]] in ''Crooked House''.
* RevisedEnding: Christie changed the endings of at least two of her novels when adapting them for the stage.
* SameFaceDifferentName: Christie also wrote six romance novels under the name Mary Westmacott.
* ShownTheirWork: Christie was an expert on poisons and how they worked, and she never missed an opportunity to show this knowledge off.
* SlidingScaleOfAnthropomorphism: There are a couple of times in the books when the narrative switches to a dog's point of view, with the dogs coming somewhat close to the "Intellectual Animal" point - examples include Bob from ''Dumb Witness'' and half a page from ''Towards Zero''.
* SomethingCompletelyDifferent: ''Literature/DeathComesAsTheEnd'', a murder mystery set in Ancient Egypt.
* SpousalPrivilege: A key plot point in ''Witness for the Prosecution''.
* StoppedClock: Used several times, in works featuring various detectives. More often subverted (e.g. it turns out the murderer set it up to mislead the detective about the time of death) than played straight.
* SuicideNotMurder: Played with in the novels, though NeverSuicide ultimately wins out 99% of the time. Occasionally one of a series of deaths will turn out to be a suicide [[spoiler:(such as in ''Dumb Witness'')]], but there is always at least ''one'' genuine homicide in each full-length novel. However, [[spoiler:in the short stories "The Market Basing Mystery" and "Murder in the Mews", as well as the stage adaptation of ''Appointment With Death'', the alleged suicides do indeed in the end turn out to be suicides]].
%%* SympatheticMurderer
%%* TakingTheHeat
%%* TapOnTheHead: Multiple instances.
%%* TenLittleMurderVictims: TropeNamer
* ThemeNaming: Christie was fond of titling her works after nursery rhymes. Novel examples include ''Literature/AndThenThereWereNone''; ''One, Two, Buckle My Shoe''; ''Literature/FiveLittlePigs''; ''Crooked House''; ''Hickory Dickory Dock''; and ''A Pocket Full of Rye''. Short stories include "Sing a Song of Sixpence", "Four and Twenty Blackbirds", "How Does Your Garden Grow", and "Three Blind Mice". Note that each of the first three lines of "Sing a Song of Sixpence" has provided the title of a work.
** And the novel ''Postern of Fate'' and the short story "The Gate of Baghdad", both of which titles came from the first quarter of the poem ''Gates of Damascus'' by James Elroy Flecker.
** ''Literature/TheMovingFinger'', a novel about blackmail in a small English village, gets its title from Edward [=FitzGerald's=] translation of "The Rubáiyát of Omar Khayyám": ''The Moving Finger writes, and having writ/Moves on: nor all thy Piety nor Wit/Shall lure it back to cancel half a Line,/Nor all thy Tears wash out a Word of it.''
%%* {{Tontine}}: Several of her books rely on them.
%%* TooDumbToLive: Anyone who blackmails a murderer.
%%* TwistEnding
* UpperClassTwit: Aristocrats are often depicted in Christie's books as silly and self-absorbed, something which Superintendent Battle lampshades in ''The Secret of Chimneys''. Examples of this are Sir Eustace Pedler (''The Man In Brown Suit'') and Lord Caterham (''Secret of Chimneys'' & ''Seven Dials Mystery''), who, in their respective novels, whines about how inconsiderate people are for dying in their properties and causing them a lot of trouble due to the subsequent scandals that occur. Even Bundle, who is a lot more sensible than her family, briefly expresses indignation when she finds out that the first victim of ''Seven Dials'' died in ''her'' room.
* TheVerse: Although Christie withstood public demands and never put Poirot and Marple in a story together, there was enough {{crossover}} among the lesser characters to show that they both lived in the same world. For instance,
** A minor character, Mr. Robinson, appeared briefly with each of Poirot and Miss Marple, as well as in ''Passenger to Frankfurt'', which featured neither of them. He also appears in ''Postern of Fate'', with Tommy and Tuppence.
** ''The Pale Horse'', which does ''not'' feature Poirot or Miss Marple, does feature Mr. and Mrs. Dane Calthorp (who had appeared in Miss Marple novel ''Literature/TheMovingFinger'') along with Ariadne Oliver, who appears in several Poirot novels, and [[spoiler:Major Despard]], one of the suspects from the Poirot novel ''Literature/CardsOnTheTable.'' [[spoiler:Rhoda Despard née Dawes]] also appears in both ''Cards on the Table'' and ''The Pale Horse''.
** Speaking of Ariadne Oliver, she first appeared as a supporting character to [[Literature/ParkerPyneInvestigates Parker Pyne]], one of Christie's lesser-known detectives; as did another of Poirot's supporting cast, Miss Felicity Lemon.
** Superintendent Battle of Scotland Yard, another of Christie's lesser-known detectives (''Towards Zero'', etc.) is a supporting character in the Hercule Poirot novel ''Literature/CardsOnTheTable'' and is mentioned in at least one other Hercule Poirot novel (''Hercule Poirot's Christmas''); his son appears in ''The Clocks'', another Poirot novel.
** Colonel Race, who also appears as a supporting character in two novels with Hercule Poirot (''Death on the Nile'' and the aforementioned ''Literature/CardsOnTheTable''), but also in ''The Man in the Brown Suit'' and ''Sparkling Cyanide'' (which are not Hercule Poirot novels).
** Another of Christie's lesser-known detectives, the elderly Mr Satterthwaite, collaborates with Poirot in the novel ''Three Act Tragedy'' and briefly appears at the start of the Poirot short story "Dead Man's Mirror," which ties the supernatural-themed [[Literature/TheMysteriousMrQuin Harley Quin stories]] into the universe.
** The Beresfords have clearly heard of Hercule Poirot enough to make jokes about him and pretend to be him while solving a case in ''Partners in Crime'', and in ''The Secret Adversary'' they meet [[spoiler: someone borrowing the identity of]] Poirot's friend Inspector Japp.
** Tapes of Christie found in 2008 state she deliberately did not want Poirot and Marple to ever meet. However, seeing this was a possibility for her to avoid, pretty much admits that Poirot and Marple are in the same universe together.
** Agatha Christie herself apparently exists in her universe; an errand boy working in an apartment building in one novel (''The Body in the Library'') mentions having the autographs of several mystery authors, including Agatha Christie.
* {{Yandere}}:
** One of her most prominent example is Vera Claythorne from ''Literature/AndThenThereWereNone'' who [[spoiler:, while working as a governess, murdered a child in her care]] so that her lover can become rich and free to marry her.
** Another good example would have to be [[spoiler: Jacqueline de Bellefort]] from ''Death on the Nile'' who [[spoiler: is the mastermind behind Linnet's murder ''and'' murdered two other witnesses who saw too much.]] And who ''still'' manages to be [[SympatheticMurderer one of the most sympathetic murderers]] in an Agatha Christie novel.
-->[[spoiler: "She cares too much, that little one."]]