History Creator / AgathaChristie

* BlackSheep: sometimes appears in BigScrewedUpFamily situations. And in Christie's works their bad reputation often turns out to be well-deserved...

* TheDogWasTheMastermind: In ''Crooked House'', the murderer turns out to be [[spoiler:the ten year old girl who was going around playing detective]].

* BewareTheNiceOnes / BewareTheQuietOnes: Part of her technique of dispelling suspicion from the actual murderer is by portraying them as friendly, genial or meek, up until the evidence suddenly becomes obvious.

* GolfClubbing: A golf club is the murder weapon in ''Spider's Web''. Subverted as an important clue in [[spoiler:''Literature/TowardsZero'', in which the murder was actually committed with, much more unusually, a tennis racket.]]

* SecretRoom: ''Spider's Web'' features one [[spoiler:in which the protagonists hide the victim's body]].

%%* BlackSheep: sometimes appears in BigScrewedUpFamily situations.

** While as noted above the Poirot, Marple, and Tommy & Tuppence series are all tied together, and several of Christie's one-off books are tied in with them, there are a few one-off Christie novels that do not have an explicit link with the main Christie universe. One of them is possibly her most famous book, ''Literature/AndThenThereWereNone''.

** Superintendent Battle of Scotland Yard, a supporting character in the Hercule Poirot novel ''Literature/CardsOnTheTable'' who is also mentioned in Poirot novel ''Literature/HerculePoirotsChristmas'', also appears in one-off novel ''Towards Zero''.

* AuthorAvatar: Ariadne Oliver, showing that Dame Agatha didn't take herself too seriously. Ariadne was a popular mystery novelist who often wrote in the bathtub with a dish of apples nearby, as Agatha did herself. Ariadne would try to help Poirot and often made the same mistakes in these "real life" cases as well as in her own writing, that Agatha herself had made in prior books. Oliver frequently laments her vegetarian Finnish detective Sven Hjerson's existence reflecting Agatha Christie's own frustrations with her Belgian NeatFreak.

* AnyoneCanDie: One plot twist Christie used was to set up a situation in which the reader expects a particular person to die [[AlwaysMurder (because of course we expect somebody to die)]] only for somebody else entirely to get murdered. And sometimes, ''[[KillEmAll everyone does.]]''

[[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 might perhaps be best described as elaborately-plotted puzzles, full of false identities and faked deaths. She enjoyed a very long career; her first novel, ''Literature/TheMysteriousAffairAtStyles'', 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]]. As of 2020, Christie still holds the top spot among the [[https://en.wikipedia.org/wiki/List_of_most_translated_individual_authors most-translated authors]] in the world.

* DirtyCop: Generally averted. In Christie's verse, police are almost always honest and diligent, if often [[PoliceAreUseless inefficient and prejudiced]]. And that concerns police everywhere, not only in Good Old England: in one of the short stories Poirot scoffs at an Englishman who thought he could bribe Herzoslovakian police to conceal a murder. If some cop turns out to have been dishonest, chances are he is not a real cop to begin with. [[spoiler: Or that you're reading ''Literature/HerculePoirotsChristmas'', though even there "dirty" is probably not the right word. Blore from ''Literature/AndThenThereWereNone'']] might be the sole example in Christie's lore where this trope was played completely straight.

** Several of the non-series books feature "Bright Young Thing" detective couples who are expies of Tommy and Tuppence. The 1982 ITV production of ''Partners in Crime'' {{lampshade|Hanging}}d this by having Tommy and Tuppence played by the same two actors who played Bobby Jones and Frankie Derwent in their 1980 adaptation of ''Why Didn't They Ask Evans?'' Between the two, James Warwick (Tommy and Bobby) also played Jimmy Thesiger in the 1981 adaptation of ''The Seven Dials Mystery'', although opposite Cheryl Campbell as Bundle, rather than Fransesca Annis. [[spoiler: And Jimmy is a subversion of the "Tommy-style" character, since he turns out to be the murderer]].

* LandDownUnder: Showing something of her Victorian upbringing, Australia (and sometimes South Africa) is home to criminals and unscrupulous adventurers, seemingly as a holdover from its founding [[SentencedToDownUnder as a British penal colony]]. Like {{Eagleland}}ers, they are often portrayed as foolish, backward, or morally lax compared to ''proper'' Englishmen and women. Many of her blackmailers and servants who steal from their employers spent time in Australia, as if the country itself attracted criminals. The CorruptCorporateExecutive in Christie books often made their fortune in one or the other, such as Simeon Lee in ''Literature/HerculePoirotsChristmas'' having discovered a number of diamond mines in South Africa. In ''Literature/SadCypress'' the villain has spent time in New Zealand and at some point [[spoiler: she]] had to leave very quickly, to avoid being arrested.

* 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 most extreme cases of this trope is the Hercule Poirot’s short story "The Adventure of the Italian Nobleman", which starts off with a physician receiving a weird phone call supposedly from his patient. The patient is soon found dead in his home, and it’s [[BlatantLies blatantly obvious]] to everybody, including [[TheWatson Hastings]], that the phone call was actually made by the killer impersonating the victim. However, the only suspect was seen leaving the victim’s home long before the phone call was made. [[spoiler: Turns out the killer made the phone call from a random phone booth after he had committed the murder and left the victim’s home. The police were so lazy and incompetent, they didn’t even bother to check the phone number from which the call came, and instead they just assumed it was made from the victim’s home.]]

* SympatheticMurderer: Christie's plots often work on a sliding scale: if a character is an AssholeVictim, expect the murderer to be treated well; if the victim was TooGoodForThisSinfulEarth, then the murderer would be remorselessly evil. The most extreme example is probably ''Murder on the Orient Express'', where the villain is a man who kidnapped and murdered a child, causing a disastrous chain effect that killed at least two other people, and the murderer [[spoiler: or rather ''murderers'' are twelve people directly affected by those deaths, prompting them to seek revenge.]] Even Poirot, who normally holds murderers in contempt regardless of their justifications, [[EveryoneHasStandards decides to let this killer go free]], coming up with another solution to satisfy the authorities.

** 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.

** To top it off, it is established that [[CelebrityParadox Christie put herself (or a fictionalization of herself) into this universe too,]] as a character in ''Literature/TheBodyInTheLibrary'' mentions having just obtained Christie's autograph, along with those of other famous crime authors.

** 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, this is pretty much an acknowledgment that Poirot and Marple exist in the same continuity together.

** AuthorAvatar Ariadne Oliver's most popular character, Sven Hjerson, is a thinly-disguised expy of Poirot. He's lanky and Finnish rather than plump and Belgian, and [[PickyEater a vegetarian who grates his vegetables]] rather than being a NeatFreak, but his creator's in-universe complaints mirror Christie's growing dislike of Poirot in real life.

** 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 (''Literature/HerculePoirotsChristmas''); his son appears in ''The Clocks'', another Poirot novel.

* ''Series/WitnessForTheProsecution'' (2016)
* ''Series/AndThenThereWereNone2015'' (2015)
*

* OddballInTheSeries: The Hercule Poirot novel ''Literature/TheBigFour''. It's most concisely described as Poirot battling a SPECTRE-style organization bent on world domination. Poirot in a ''Film/JamesBond'' style mystery, facing an evil alliance consisting of an English MasterOfDisguise, a French MadScientist, an American CorruptCorporateExecutive and a YellowPeril style mastermind.

* OddballInTheSeries: The Hercule Poirot novel ''Literature/TheBigFour''. It's most concisely described as Poirot battling a SPECTRE-style organization bent on world domination. Poirot in a ''Series/JamesBond'' style mystery, facing an evil alliance consisting of an English MasterOfDisguise, a French MadScientist, an American CorruptCorporateExecutive and a YellowPeril style mastermind.

* {{Eagleland}}: As a rather old-fashioned British subject, it should be no surprise that her depictions of Americans in her works were just a little... off (particularly in terms of their accent and [[SeparatedByACommonLanguage any use of idiomatic language]]). In fact, you pick up early on that if one of her characters is American, or is an British subject who spent any significant time there, that person is usually an AssholeVictim, a buffoon, or a weak criminal type. [[spoiler:They are, however, rarely important enough to be the actual murderer.]] And of course, there's [[Literature/MurderOnTheOrientExpress the case where everyone has ties to America]]; [[spoiler:[[EverybodyDidIt they all can't have done it]], right?]]

* 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''). In ''Literature/TheyCameToBaghdad'' the heroine falls in love with an archaeologist. This interest eventually led Christie to actually set one novel in ancient Egypt itself (''Literature/DeathComesAsTheEnd''). Her work on digs ended up making her an expert on Mesopotamian pottery - reportedly, she once asked an archaeologist friend who the greatest authority on a particular kind of pottery was, as she wanted to consult them, only to be told it was ''her''.