In Agatha Christie's mystery novels, several characters cross over different sagas, creating a fictional universe in which most of her stories are set. This article has one table to summarize the novels with characters who occur in other Christie novels; the table is titled Crossovers by Christie. There is brief mention of characters crossing over in adaptations of the novels. Her publications, both novels and short stories, are then listed by main detective, in order of publication. Some stories or novels authorised by the estate of Agatha Christie, using the characters she created, and written long after Agatha Christie died, are included in the lists.
Her novels under the pen name Mary Westmacott and her nonfiction books are not covered in this article.
One notable example of characters from one novel appearing in another is the novel The Pale Horse, which featured no fewer than five cross-over characters: Ariadne Oliver, Major Despard and his wife Rhoda (all had previously appeared in the Poirot mystery Cards on the Table; although Mrs Oliver appeared in numerous later Poirot mysteries) and the Rev and Mrs Dane Calthrop (who were seen in the Miss Marple mystery The Moving Finger).
List of cross-overs
Crossovers by Christie
Crossovers in media adaptations of novels or short stories
Outside of stories by Christie herself, three media adaptations of her works have featured crossovers involving Miss Marple which Christie herself never wrote; two of the three aired many decades after her death: The Alphabet Murders (1966 film) features a meeting between Poirot and Marple, where they exchange glances. Agatha Christie's Great Detectives Poirot and Marple, a 2004 anime series, connects the two. The 2006 adaptation of By the Pricking of My Thumbs, as episode 7 (season 2 episode 3) of Agatha Christie's Marple, has Marple meet Tuppence while Tommy is away.
List of novels & short stories by featured detective
Hercule Poirot
The Mysterious Affair at Styles (1920 novel) The Adventure of the Western Star (1923 short story) The Tragedy at Marsdon Manor (1923 short story) The Adventure of the Cheap Flat (1923 short story) The Mystery of Hunter's Lodge (1923 short story) The Million Dollar Bond Robbery (1923 short story) The Adventure of the Egyptian Tomb (1923 short story) The Jewel Robbery at the Grand Metropolitan (1923 short story) The Kidnapped Prime Minister (1923 short story) The Disappearance of Mr Davenheim (1923 short story) The Adventure of the Italian Nobleman (1923 short story) The Case of the Missing Will (1923 short story) Christmas Adventure (1923 short story) The Affair at the Victory Ball (1923 short story) The Adventure of the Clapham Cook (1923 short story) The Cornish Mystery (1923 short story) The Adventure of Johnnie Waverly (1923 short story) The Double Clue (1923 short story) The King of Clubs (1923 short story) The LeMesurier Inheritance (1923 short story) The Lost Mine (1923 short story) The Plymouth Express (1923 short story) The Chocolate Box (1923 short story) The Veiled Lady (1923 short story) The Submarine Plans (1923 short story) The Market Basing Mystery (1923 short story) The Murder on the Links (1923 novel) The Murder of Roger Ackroyd (1926 novel) The Under Dog (1926 short story) The Big Four (1927 novel) Double Sin (1928 short story) Wasp's Nest (1928 short story) Alibi (1928 play) The Third Floor Flat (1929 short story) Black Coffee (1930 play) Peril at End House (1932 novel) The Mystery of the Bagdad Chest (1932 short story) Lord Edgware Dies (1933 novel) Murder on the Orient Express (1934 novel) Death in the Clouds (1935 novel) The A.B.C. Murders (1936 novel) Murder in the Mews (1936 novella) Triangle at Rhodes (1936 novella) Problem at Sea (1936 short story) Poirot and the Regatta Mystery (1936 short story) The Incredible Theft (1937 novella) Yellow Iris (1937 short story) The Dream (1937 short story) Dumb Witness (1937 novel) Death on the Nile (1937 novel) Wasp's Nest (1937 TV play) The Yellow Iris (1937 radio play) Appointment with Death (1938 novel) Hercule Poirot's Christmas (1938 novel) Sad Cypress (1940 novel) One, Two, Buckle My Shoe (1940 novel) Four and Twenty Blackbirds (1941 short story) Evil Under the Sun (1941 novel) Five Little Pigs (1942 novel) The Hollow (1946 novel) Taken at the Flood (1948 novel) After the Funeral (1953 novel) The Adventure of the Christmas Pudding (1960 novella) The Mystery of the Spanish Chest (1960 novella) Curtain (1975 novel) The Incident of the Dog's Ball (2010 short story) The Capture of Cerberus (2010 short story)