The Maltese Falcon is a 1930 detective novel by Dashiell Hammett, originally serialized in the magazine Black Mask. The story has been adapted several times for the cinema. The main character, Sam Spade, appears only in this novel and in three lesser known short stories, yet is widely cited as the crystallizing figure in the development of the hard-boiled private detective genre ? Raymond Chandler's character Philip Marlowe, for instance, was strongly influenced by Hammett's Spade. Spade was a departure from Hammett's nameless detective, The Continental Op. Sam Spade combined several features of previous detectives, most notably his cold detachment, keen eye for detail, and unflinching determination to achieve his own justice.

In 1998, the Modern Library ranked The Maltese Falcon 56th on its list of the 100 best English-language novels of the 20th century.

In this novel, Hammett redefines many of the conventions of the "hard-boiled" detective genre. Spade is a bitter, sardonic character who lets the police and the criminals think he is in with the criminals while he works singlemindedly to catch the crooks. Brigid O'Shaughnessy is the classic femme fatale. The other crooks are manipulative and self-centered (or merely self-centered) with no concern for anyone's well-being except their own.

However, unlike some other hard-boiled detectives who have a strong sense of idealism underneath the cynical shell, Hammett never provides a clear statement of Spade's notion of morality. Spade attempts to explain himself to Brigid O'Shaughnessy with the Flitcraft parable, in which Hammett makes an oblique reference to the philosopher Charles Sanders Peirce, but O'Shaughnessy has no idea what he is getting at.

The novel has been filmed three times, twice under its original title. The Maltese Falcon (1931), was the first version and pre-Code production starring Ricardo Cortez and Bebe Daniels. Satan Met a Lady (1936), was a light-comedy adaptation starring Bette Davis and Warren William, with Sam Spade becoming "Ted Shane". The Maltese Falcon (1941) is the third version -- considered to be a film noir classic, starring Humphrey Bogart, Mary Astor, Peter Lorre, and Sydney Greenstreet.