Antihero

While a traditional hero might be counted on to do the right thing for the common good, the protagonist of The Maltese Falcon, Sam Spade, responds to every situation by examining what he himself stands to gain from it. Spade is willing to betray his friends, and he has an affair with his business partner's wife. He does not work within the law, but checks in with his lawyer regularly to see how far outside of the law he can go. And he is an untrusting lover, accusing Brigid O'Shaughnessy of duplicity the moment that the falcon is discovered to be fake. Hammett establishes his questionable moral position in the novel's first paragraph, describing him as looking "rather pleasantly like a blond Satan."

In the end, Spade explains to Brigid O'Shaughnessy that his seemingly amoral behavior is just a ruse that he uses to draw criminals to him...