John Klempner's 1945 novel, A Letter to Five Wives, was adapted by Vera Caspary and Joseph L. Mankiewicz into the 1949 film, A Letter to Three Wives. It was directed by Mankiewicz and stars Jeanne Crain, Linda Darnell, Ann Sothern, Kirk Douglas, Paul Douglas in his film debut, Jeffrey Lynn, and Thelma Ritter. The film won the Academy Awards for Best Director and Best Writing, Screenplay and was nominated for Best Picture.

There is no information about the novel available on Wikipedia at this time, but here is a link to the film entry.