The "locked-room" or "impossible crime" mystery is a subgenre of detective fiction in which a crime (almost always murder) is committed in circumstances under which it was seemingly impossible for the perpetrator to commit the crime or evade detection in the course of getting in and out of the crime scene. The crime in question typically involves a crime scene with no indication as to how the intruder could have entered or left, i.e., a locked room. Following other conventions of classic detective fiction, the reader is normally presented with the puzzle and all of the clues, and is encouraged to solve the mystery before the solution is revealed in a dramatic climax.
To investigators of the crime, the prima facie impression almost invariably is that the perpetrator has vanished into thin air. The need for a rational explanation for the crime is what drives the protagonist to look beyond these appearances and solve the puzzle.
Though the mystery or detective genre was not established until the 19th century, there are notable predecessors in ancient writings. The deuterocanonical Old Testament story "Bel and the Dragon" has some similarities to locked-room mysteries; the hero Daniel debunks the worship of an idol that supposedly eats food offerings left for it in a sealed room, by exposing the secret entrance used by the priests who take the food for themselves. In the 5th century BC, Herodotus told the tale of the robber whose headless body was found in a sealed stone chamber with only one guarded exit. Honoré de Balzac in La Comedie Humaine (1799–1850): Maitre Cornelius (1846) and Alexandre Dumas, père in Les Mohicans de Paris: La Visite Domiciliaire (1854) included locked-room elements in their novels.
The earliest fully-fledged example of this type of story is generally held to be Edgar Allan Poe's "The Murders in the Rue Morgue" (1841). Wilkie Collins' The Moonstone (1868) features a rudimentary locked-room murder. A number of authors, including Joseph Conrad, Sheridan Le Fanu, and Dick Donovan, tried their hand at the new genre, but their ingenuity extended only to secret passages, duplicate keys, and diabolical mechanical devices. It was not until publication of Israel Zangwill's work The Big Bow Mystery (1892) that the hallmark of every great impossible crime—"misdirection"—made its appearance, introducing a murder technique much emulated since. The other great early work, Le Mystère de la Chambre Jaune (The Mystery of the Yellow Room), was written in 1907 by French journalist and author Gaston Leroux; it, too, has had many imitators.
In the Golden Age of Detective Fiction impossible crimes were mainly solved by brilliant amateur sleuths, inspired by Arthur Conan Doyle's creation Sherlock Holmes, who were inexplicably given free rein by Scotland Yard and, to a markedly lesser extent in their American equivalents, the New York Police Department; puzzling mysteries were solved by sheer reasoning and brain power. Such creators of famous Anglo-Saxon amateur detectives as Jacques Futrelle, Thomas and Mary Hanshew, G. K. Chesterton, Carolyn Wells, John Dickson Carr, C. Daly King, and Joseph Commings turned out novels featuring impossible crimes in vast quantities. To a lesser degree, Christianna Brand, Agatha Christie, Ellery Queen, Clayton Rawson, and Hake Talbot did the same. Authors such as Nigel Morland and Anthony Wynne, whose output leaned more toward science-based detective stories, also tried their hand at impossible mysteries.
In French, Pierre Boileau, Thomas Narcejac, Gaston Boca, Marcel Lanteaume, Pierre Very, Noel Vindry and the Belgian Stanislas-Andre Steeman were other important impossible crime writers, Vindry being the most prolific with 16 novels. Edgar Faure, later to become Prime Minister of France, was a not particularly successful contemporary.
During the Golden Age of Detective Fiction, English-speaking writers dominated the genre, but after the 1940s there was a general waning of English-language output. French authors continued writing into the 1950s and early 1960s, notably Martin Meroy and Boileau-Narcejac, who joined forces to write several locked-room novels. They also co-authored the psychological thrillers which brought them international fame, two of which were adapted for the screen as Vertigo (1954 novel; 1958 film) and Diabolique (1955 film). The most prolific writer during the period immediately following the Golden Age was Japanese: Akimitsu Takagi wrote almost 30 locked-room mysteries, starting in 1949 and continuing to his death in 1995. A number have been translated into English.
John Dickson Carr, who also wrote as Carter Dickson, is probably the crime fiction writer most closely associated with locked room and impossible crime puzzles, which feature in most of his dozens of mystery novels. His 1935 novel The Hollow Man (US title: The Three Coffins) was in 1981 voted the best locked-room mystery novel of all time by 17 authors and reviewers, although Carr himself names Gaston Leroux's The Mystery of the Yellow Room (1907-1908) as his favorite. (Leroux's novel was named third in that same poll; Hake Talbot's Rim of the Pit (1944) was named second.) Three other Carr/Dickson novels were in the top ten of the 1981 list: The Crooked Hinge (1938), The Judas Window (1938), and The Peacock Feather Murders (1937).
The genre continued into the 1970s. Bill Pronzini's Nameless Detective novels feature locked-room puzzles. The most prolific creator of impossible crimes is Edward D. Hoch, whose short stories feature a detective, Dr. Sam Hawthorne, whose main role is as a country physician. The majority of Hoch stories feature impossible crimes; one appeared in EQMM every month from May 1973 through January 2008. Hoch's protagonist is a gifted amateur detective who uses pure brainpower to solve his cases.
The French writer Paul Halter, whose output of over 30 novels is almost exclusively of the locked-room genre, has been described as the natural successor to John Dickson Carr. Although strongly influenced by Carr and Agatha Christie, he has a unique writing style featuring original plots and puzzles. A collection of ten of his short stories, entitled The Night of the Wolf, has been translated into English.
The Japanese writer Soji Shimada has been writing impossible crime stories since 1981 and has created 13 to date. The first, The Tokyo Zodiac Murders (1981), is the only one to have been translated into English. The themes of the Japanese novels are far more grisly and violent than those of the more genteel Anglo-Saxons. Dismemberment is a preferred murder method. Despite the gore, the norms of the classic detective fiction novel are strictly followed.
Umberto Eco, in the 2000 novel Baudolino, takes the locked-room theme into medieval times. The book's plot suggests that Emperor Frederick I had not drowned in a river, as history records, but died mysteriously at night while a guest at the castle of a sinister Armenian noble. The book features various suspects, each of whom had a clever means of killing the Emperor without entering the room where he slept - all these means having been available in medieval times.
The locked-room genre has also been translated into children's detective fiction, although the crime committed is usually less severe than murder. One notable example would be Enid Blyton, who wrote several juvenile detective series, often featuring seemingly impossible crimes that her young amateur detectives set out to solve.
The Hardy Boys novel "While the Clock Ticked" was (originally) about a locked and isolated room where a man seeks privacy, but receives mysterious threatening messages there. The messages are delivered by a mechanical device lowered into the room through a chimney.
King Ottokar's Sceptre (1938–1939) is the only Tintin adventure that is a locked-room mystery. No homicide is involved. The crime is the disappearance of the royal sceptre that is bound to have disastrous consequences for the king.
Pulp magazines in the 1930s often contained impossible crime tales, dubbed weird menace, in which a series of supernatural or science-fiction type events is eventually explained rationally. Notable practitioners of the period were Fredric Brown, Paul Chadwick and, to a certain extent, Cornell Woolrich, although these writers tended to rarely use the Private Eye protagonists that many associate with pulp fiction.
Quite a few comic book impossible crimes seem to draw on the "weird menace" tradition of the pulps. However, celebrated writers such as G. K. Chesterton, Arthur Conan Doyle, Clayton Rawson, and Sax Rohmer have had their works adapted to comic book form. In 1934, Dashiell Hammett created the comic strip Secret Agent X9, illustrated by Alex Raymond, which contained a locked-room episode, albeit a rather feeble one. One American comic book series that made good use of locked-room mysteries is Mike W. Barr's Maze Agency.