How does sam spade from the Maltese falcon change throughout the story?

In "The Maltese Falcon," Sam Spade evolves from a self-serving private detective to a more morally complex character. Initially motivated by personal gain and seduction, he becomes disillusioned with the corrupt world around him, particularly through his interactions with Brigid O'Shaughnessy and the various criminals pursuing the falcon. By the end, Spade demonstrates a commitment to justice over personal desire, ultimately choosing to turn Brigid in rather than succumbing to her manipulations. This transformation highlights his integrity and the moral ambiguities of his profession.