The Postman Always Rings Twice is a 1934 crime novel by American writer James M. Cain. The novel was successful and notorious upon publication. It is considered one of the most outstanding crime novels of the 20th century. The novel's mix of sexuality and violence was startling in its time and caused it to be banned in Boston. It is included in Modern Library's list of 100 best novels, and it was published as an Armed Services Edition during WWII. The novel has been adapted for film seven times, of which the 1946 version is regarded as an important film noir. The story owes a clear debt to Émile Zola's 1868 novel Thérèse Raquin, which has a similar plot. Source: Wikipedia (en)