ler, The Big Sleep, also predates the film version by about a decade.
For much of the thirties and forties, the detective in the mold of Sherlock Holmes--the consulting detective, often a private individual rather than a police official, sometimes a gifted amateur rather than a professional--was common, with several different series characters exemplifying this genre. Television took this form over wholeheartedly, and perhaps this contributed to its decline in theaters. In addition, of course, the strict detective-mystery form was complemented and eventually all but supplanted by the private detective film, a related genre with somewhat different conventions. The private eye film has also gone in and out of favor, though it has never disappeared entirely, and it has also been taken over to a great extent by television. The shift to the private eye occurred along with a change in social attitudes beginning in 1940. Prior to the release of The Maltese Falcon, the detective was nearly always portrayed as the implacable and usually unflappable foe of the criminal. What interested the detective was discovering the answer who committed the crime, how did he or she do it, and why. The questions were simple even if the answers were not. After The Maltese Falcon, the questions and answers alike were more complex, as was the detective himself and for the private eye genre until recently, "himself" is the correct word. The private eye was exclusively male and operated in a shadowy world, where the detective had operated in the light. The private eye was more an anti hero than a hero, and as the form developed, he only became more of an ambiguous character.
The private eye operates by a complex code that decides his actions, and this code does not necessarily coincide with the law. In The maltese Falcon, Sam Spade investigates the death of his partner because the private eye is expected to do that, even when he did not like his...