FAQ

When asked for an explanation, Cain stated that the manuscript had been rejected by 13 publishers prior to being accepted for publication on his 14th attempt, so that when the publisher asked him what he wanted the work to be entitled he drew on this experience and suggested The Postman Always Rings Twice. -- Wikipedia page for " The Postman Always Rings Twice"

Probably no one was more surprised at the worldwise reaction to The Postman Always Rings Twice when it was published in 1934 than its author, James M. Cain. His little novel rocked readers and critics as they had never been rocked before. Cain had described Postman simply as being about 'a couple of jerks who discover that murder, though dreadful enough morally, can be a love story, too, but then wake up to discover that once they've pulled the thing off, no two people can share this terrible secret.' It was his favorite theme, which he had already developed in his 1928 short story "Pastorale" and would use again in his 1936 Liberty magazine serial, Double Indemnity. Cain, who was 42 when Postman was published, thought the book might sell a few thousand copies, if he was lucky, and maybe he would have another idea for a novel.

But Postman was that rare achievement - a literary success that was also a best-seller which kept on selling and selling around the world and down through the years. -- Roy Hoopes (ed.), Career C and Other Fiction, NY, 1986

dear mr. r [Frank Rosengren, a book seller] . . .

am enclosing check for two dollars for 'postman rings twice.' it arrived with one ring since our postman is no mental epicure. -- Joe McCarthy (ed.), Fred Allen's Letters, NY, 1965, p. 125 (lower case letters in the original)