The core of Hammett's art is his version of the masculine figure in American society. The Continental Op constitutes the basic pattern for this figure, which in the body of Hammett's work undergoes a revealing development.

The older detectives of literature—exemplified most unequivocally by the figure of Sherlock Holmes—stood on a firm social and moral basis, and won their triumphs through the exercise of reason…. The question of his motives never arises, simply because it is answered in advance: he is one of the great army of good men fighting, each in his own way, against evil…. With Hammett, the moral and social base is gone; his detectives would only be amused, if not embarrassed, by any suggestion that they are "doing their duty"—they are merely doing.

The Op is primarily a job-holder: all the stories in which he appears begin with an assignment and...