The prevailing view is that existentialism is a product of post World War II Europe and had no significant presence in the United States before the 1940s. Jean-Paul Sartre and associates are credited with establishing the philosophy in France, and later introducing it to Americans. But conventional wisdom about existentialism in the United States is mistaken. The United States actually developed its own unique brand of existentialism several years before Sartre and company published their first existentialist works. Film noir, and the hard-boiled fiction that served as its initial source...