Which author created the detective Sam Spade?

The author who created the detective Sam Spade is Dashiell Hammett. Hammett introduced Spade in 'The Maltese Falcon', a 1930 novel that helped define the hard-boiled American detective story.

Spade is a private investigator working in San Francisco. Unlike the detached puzzle-solvers of many Golden Age mysteries, he operates in a morally uncertain world shaped by violence, money, betrayal, and competing loyalties. His sharp dialogue, guarded emotions, and willingness to bend rules became influential features of noir fiction.

Hammett drew on his own experience as a Pinkerton detective, although Sam Spade is a fictional character rather than a direct self-portrait. The Maltese Falcon was adapted several times for film, most famously in John Huston's 1941 version starring Humphrey Bogart. Readers sometimes confuse Spade with Philip Marlowe, Raymond Chandler's private eye, but Chandler created Marlowe; Hammett created Spade. Hammett also created Continental Op, another important hard-boiled detective.