Howard Hawks's 'The Big Sleep' is a quintessential film noir, adapting Raymond Chandler's novel with a plot so tangled that even its makers reportedly could not fully untangle it. Humphrey Bogart plays private eye Philip Marlowe, drawn into blackmail, gambling and murder among a wealthy family, sparring with Lauren Bacall in crackling, innuendo-laced exchanges. The byzantine story matters less than the atmosphere, wit and star chemistry. It stands as one of the defining detective films of the classic era.