The classic film noir era is usually dated from the early 1940s to the late 1950s. The films were often adaptations of American crime novels, which were also described as "hardboiled". Some authors resisted these terms. For example, James M. Cain, author of "The Postman Always Rings Twice" (1934) and "Double Indemnity" (1944), is considered to be one of the defining authors of hard-boiled fiction. Both novels were adapted as crime films, the former more than once. Cain is quoted as saying, "I belong to no school, hard-boiled or otherwise, and I believe these so-called schools exist mainly in the imagination of critics, and have little correspondence in reality anywhere else."