It is my belief that although Poe’s Dupin, in The Purloined Letter, and Hammet’s Spade, in The Maltese Falcon both have very unique qualities, they both share very similar moral codes. These codes of morality, they would like to believe, have no bearing on the world or society around them. They both follow their own moral standards and do not follow what is expected of them. As Spade repeatedly suggests that honesty and loyalty are not what he is concerned about. As it occurs in both cases, Dupin and Spade act as investigators, but to do their eccentric moral standards, they must mysteriously work around the men in uniform.
They are unconventional. Unusual investigation tactics that were used such as bribery, which Spade tried against Cairo were not uncommon for characters like these (chapter 5). Likewise, Dupin, solves the theft by putting himself at risk politically. Unlike the uniformed investigators, Dupin is able to solve the case by detaching himself emotionally. It is clear, however, the both Spade and Dupin are driven to solve the cases due to personal revenge or personal motive. In the end, both of these characters become the hero of the story.
In Spade’s case, although his motives might be self-righteous, he is able to find and turn in the killer. Dupin solves most of his cases on personal intuition; however, he as well becomes the hero as he solves the theft of the letter.2.
Although it may not be apparent throughout the entire novel, Spade reveals himself as an archetypal hero through professional integrity at the end. Sam Spade is a character who has never conformed.