The characters were originally invented by Richard for some vignettes he wrote for the New York Sun during the early thirties and which he later resurrected in the short domestic comedies he contributed to The New Yorker, by which time the Norths had acquired their full names but not yet their abilities as amateur detectives. A collection of the stories was published in 1936 as Mr. and Mrs. North. The crime novels originated when Frances Lockwood started writing a mystery during one summer vacation. Stuck on a plot complication she called on her husband for help and the writing team was launched. Because the Norths already had some name recognition, the Lockridges decided to use Pam and Jerry as their central characters and retain the humorous tone and the playful interaction between the couple from the earlier stories. The first Mr. and Mrs. North mystery, The Norths Meet Murder, was published in 1940.