The pair wrote 50 novels together,[1] including one of the most famous American mystery series, Mr. and Mrs. North.
They also wrote other series, including Lt Heimrich, Nathan Shapiro, and Paul Lane.
A retired college professor who first assists Heimrich with a case in Accent on Murder (1958) and again in Murder Can't Wait (1964)—a book that also features the meeting of Nathan Shapiro and Merton Heimrich—shows up to help ADA Bernie Simmons in Twice Retired (1970).
Bill Weigand, who as a homicide lieutenant was the police friend of Mr. and Mrs. North throughout their series, is referred to occasionally as the division captain in the Paul Lane book.
In their collaborations, Frances would generally produce the plot of the novels, while Richard would flesh out the writing.
Richard Lockridge collaborated with his wife, using her plot and the characters he had created earlier for a series of comic sketches in The New Yorker, Mr. and Mrs. North (named for the "stupid people who played the north hand in bridge problems," according to Lockridge).
The book was published in 1940 as The Norths Meet Murder, launching a series of twenty-six novels, which was adapted for the stage, film, radio, and television.
There they meet an officer of the New York State Bureau of Criminal Identification (referred to in some later books as the Bureau of Criminal Investigation), Lt. Heimrich (in later books given the first name Merton, and achieving promotion to Captain).
Richard and Frances co-wrote the first four novels in the series, and it eventually ran to ten books.
Lane was the main character in Quest for the Bogeyman (1964), and then he and partner Sgt., then later Lt., John Stein, were prominently featured in the six novels focused on New York County assistant district attorney Bernard Simmons that followed that character's first appearance, in And Left for Dead (1961).
(The novels featuring the interplay and occasional conflicts between ADA Bernie Simmons and Lane and Stein prefigures the Law & Order television series.)