Before the Fact (1932) is a novel by Anthony Berkeley writing under the pen name "Francis Iles".

Iles' novel is experimental in that it is not a whodunit: It does not take long to determine the identity of the villain and his motives. According to Colin Dexter, Before the Fact is a "crime novel" rather than a "detective novel", with Iles being "the father of the psychological suspense novel as we know it today" for his authorship of Malice Aforethought (1931) and Before the Fact (1932). It is true that the police do not play any role in the book; none of the characters are ever charged with a crime, let alone indicted for or convicted of one. Dark and suspenseful, Berkeley's thriller was adapted into the classic film Suspicion, directed by Alfred Hitchcock

For the Hitchcock film, the inverted detective story format was eliminated, making Johnnie's murderous indiscretions merely a product of Lina's imagination. According to William L. De Andrea in Encyclopedia Mysteriosa (1994), this was because the studio, RKO Radio Pictures, was uncomfortable with the idea of having one of Hollywood's leading actors Cary Grant, who played Johnnie, being shown on screen as a devious psychopath.

Hitchcock was quoted as saying that he was forced to alter the ending of the movie.[1] He wanted an ending similar to the climax of the novel, but the studio, more concerned with Cary Grant's "heroic" image, insisted that it be changed. Writer Donald Spoto, in his biography of Hitchcock The Dark Side Of Genius, disputes Hitchcock's claim to have been overruled on the film's ending. Spoto claims that the first RKO treatment and memos between Hitchcock and the studio show that Hitchcock emphatically desired to make a film about a woman's fantasy life.