A whodunit ("Who done it?") is a detective novel where the reader is provided with clues and encouraged to take guesses at who the perpetrator -- in most cases the murderer -- is. The identity is only revealed in the final pages of the book. Whodunits are essentially puzzles in the form of a story.
The subgenre of the whodunit flourished during the so-called "Golden Age" of the 1920s and 1930s, when it was the predominant mode of crime writing. Most of the authors on both sides of the Atlantic have long been forgotten since, with the exception of a handful of writers whose novels have become classics and have been in print ever since their first publication.
Most authors were British -- Agatha Christie (b. 1890, d.1976), Dorothy L. Sayers (b. 1893, d. 1957), Josephine Tey (b. 1896, d. 1952), and Cyril Hare, for example. Some of them -- John Dickson Carr, for example -- were American, but with a very British touch.
By that time certain conventions and clichés had been established which limited any surprises on the part of the reader to the twists and turns within the plot and of course to the identity of the murderer. Several authors excelled, after successfully leading their readers on the wrong track, in convincingly revealing to them the least likely suspect as the real villain of the story. What is more, they had a predilection for certain casts of characters and settings, with the secluded English country house at the top of the list.
A U.S. reaction to the cosy conventionality of British murder mysteries was the American hard-boiled school of crime writing (Raymond Chandler, Dashiell Hammett, Mickey Spillane -- cf. his novel I, the Jury -- , and others).
Some representative examples of whodunits in chronological order:
- Anna Katharine Green's Initials Only (1911) (Project Gutenberg Etext #1857)
- E. C. Bentley's Trent's Last Case (1913)
- Dorothy L. Sayers's Whose Body? (1923), in which her famous detective Lord Peter Wimsey is introduced
- Agatha Christie's The Murder of Roger Ackroyd (1926), featuring her famous creation, Belgian sleuth Hercule Poirot, and in which the solution to the crime is related to the narrative technique of the novel.
- Ronald Knox's The Footsteps at the Lock (1928) -- though Knox is better remembered as (a) a clergyman and (b) the author of ten commandments for writing whodunits
- Anthony Berkeley's The Poisoned Chocolates Case (1929)
- C.P. Snow's Death Under Sail (1932) -- his first novel, after which he turned to mainstream fiction
- John Dickson Carr's (aka Carter Dickson's) The Hollow Man (1935) -- the classic example of a locked room mystery, complete with a philosophical digression in which the detective, Dr Gideon Fell, lectures on the "hermetically sealed chamber"
- Josephine Tey's A Shilling for Candles (1936) -- which became the basis for Alfred Hitchcock´s 1937 film Young and Innocent
- Ethel Lina White's The Wheel Spins (1936) -- which again was filmed by Hitchcock as The Lady Vanishes (1938) (with an ending which is wildly different though)
- Cyril Hare's Tragedy at Law (1942)
Finally, recent additions to the subgenre of the whodunit include the novels of Simon Brett, Lawrence Block's The Burglar in the Library (1997), which is a spoof set in the present in an English-style country house, Kinky Friedman's Road Kill (1997), and Ben Elton's Dead Famous (2001).
- See also Historical whodunnit.
In reaction to the whodunit's popularity, there is also the "howhescatchem" story where the guilty party and the crime is openly revealed to the reader/audience and the story follows the investigator's efforts to find out the truth while the criminal attempts to prevent it. The Columbo TV movie series is the classic example of this kind of detective story. This tradition was begun as early as 1931 with the publication of Malice Aforethought by Anthony Berkeley writing as Francis Iles. In the same vein, Iles published Before the Fact (1932), which became the Hitchcock movie Suspicion. Today, these novels are seen as the predecessors of the psychological suspense novel (Patricia Highsmith's This Sweet Sickness, 1960; Simon Brett's A Shock to the System, 1984; Stephen Dobyns's The Church of Dead Girls, 1997; and many more).
- See also crime fiction for an overview.