Golden Age of Detective Fiction

The Golden Age of Detective Fiction names the era of murder-mystery novels predominantly in the 1920s and 1930s, though similar fiction appeared from at least 1911 and has never fully stopped. The scene was overwhelmingly British and Irish: Agatha Christie, Dorothy L. Sayers, Margery Allingham and Ngaio Marsh were collectively called the Queens of Crime, with S. S. Van Dine, Ellery Queen, Rex Stout and John Dickson Carr among the Americans who worked the same vein. Its stage was the secluded English country house stocked with upper-class suspects, the skeleton later echoed by the board game Cluedo.

The era codified fair play. The novels were puzzle whodunits in which the criminal appears early and the detective shares the clues, and the rules were written down: Ronald Knox's Decalogue in 1929 and S. S. Van Dine's Twenty Rules in 1928. The Detection Club, founded in 1930, had its members agree to follow Knox's commandments. That contract is the direct ancestor of the fair-play mystery tradition and of the showcase whodunit and locked-room mystery forms.

World War II is commonly treated as the boundary: Ian Ousby writes that it "marked a significant close, just as the First World War had marked a significant beginning". The style survived in the cozy mystery, in television such as Murder, She Wrote and Midsomer Murders, and in Japan's shin honkaku school from the late 1980s.