The Big Sleep (1939) is a hardboiled crime novel by Raymond Chandler, the first to feature the detective Philip Marlowe. It has been adapted for film twice, in 1946 and again in 1978. The story is set in Los Angeles

The story is noted for its complexity, with characters double-crossing one another and secrets being exposed throughout the narrative. The title is a euphemism for death; the final pages of the book refer to a rumination about "sleeping the big sleep".

In 1999, the book was voted 96th of Le Monde's "100 Books of the Century". In 2005, it was included in Time magazine's "List of the 100 Best Novels".