The novels often display a marked class consciousness, reflecting the influence of the Depression. The detectives often seem as much victims of circumstances themselves as master sleuths solving crimes and restoring order. The novels are interested in psychology, often pathological psychology, thus reflecting the influence of psychoanalysis. As with film noir, there is often a pervasive fear of sexuality and anxiety that seems to be linked to the changing roles of men and women in society. The language is marked by wise-cracks and the use of contemporary slang.
Characters often talk around a point while the real subject of the conversation remains unsaid.
The noir detective discovers darkness everywhere, finds it to be life's ruling principle, and learns that even the rich and privileged are usually no better than the poor and deprived. In the battle between good and evil, the greater strength is wielded by the latter. This fictional world is not ordered by poetic justice but by an amoral determinism. People are inherently evil and self-centered. Death comes unexpectedly to all.