James M. Cain owed so much too screenwriters who adapted his books for movies.
The work of Raymond Chandler and Billy Wilder elevated "Double Indemnity."

It amused me that Cain used to bellyache at how so many hard boiled books and film scripts copied his plots. Cain made a career out of revising the details of the infamous Ruth Snyder and Judd Gray murder case in New York City and passing it off as a wholly original work of fiction.