Completed in 1934 and nominated for the Academy Award for Best Picture, the film was directed by W.S. Van Dyke from a script by Albert Hackett and Frances Goodrich; the screenplay was based on the mystery novel The Thin Man by Dashiell Hammett, supposedly based on his relationship with playwright Lillian Hellman. Also appearing in the film were Maureen O'Sullivan, Nat Pendleton, Minna Gombell, Cesar Romero and Porter Hall.
In 1997, the film was added to the United States National Film Registry having been deemed "culturally, historically, or aesthetically significant."
The "Thin Man" in the title of the film The Thin Man was actually the lead suspect, but the name was thought by virtually everyone to refer to Nick Charles, and it was used in the titles of the sequels, although no one ever called him that.
During TCM Thin Man Marathon I decided to tweet the question. Here some interesting answers from fellow TCManiacs: