The private detective story is a different matter entirely. Raymond Chandler famously likened the private eye to a knight, a man who could walk mean streets but not himself be mean, and this is true of the overwhelming majority of those heroic figures. They may well be brought into an exceedingly dark situation, and encounter characters who are deceptive, violent, paranoid, and lacking a moral center, but the American private detective retains his sense of honor in the face of all the adversity and duplicity with which he must do battle. Sam Spade avenged the murder of a partner because he knew he “was supposed to do something about it.” Mike Hammer found it easy to kill a woman to whom he had become attached because he learned she had murdered his friend. Lew Archer, Spenser, Elvis Cole, and other iconic private eyes, as well as policemen who, like Harry Bosch and Dave Robicheaux, often act as if they are unconstrained by their official positions, may bend (or break) the law, but their own sense of morality will be used in the pursuit of justice. Although not every one of their cases may have a happy conclusion, the hero nonetheless will emerge with a clean ethical slate.
Film noir blurs the distinction between hard-boiled private eye narratives and true noir stories by employing similar design and camerawork techniques for both genres, though the discerning viewer will easily recognize the opposing life-views of a moral, even heroic, often romantic detective, and the lost characters in noir who are caught in the inescapable prisons of their own construction, forever trapped by their isolation from their own souls, as well as from society and the moral restrictions that permit it to be regarded as civilized.