The Shadow was a popular Old Time Radio show that aired for 22 years, from 1932 to 1954. It followed the adventures of amateur detective Lamont Cranston and his companion Margo Lane, with Cranston using his secret ability to cloud men's minds and become invisible to fight on the side of law enforcement. Throughout its run, the series featured notable actors like Orson Welles, Agnes Moorehead, Frank Readick, Bill Johnstone, and Bret Morrison. Today, only about a third of the aired episodes are still available.

The character was originally created as a mysterious radio show narrator and developed by writer Walter B. Gibson for Street & Smith Publishers. The Shadow quickly gained popularity, leading to adaptations in comic books, comic strips, serials, video games, and films.

The radio drama had several different versions, but the most iconic iteration began on September 26, 1937, starring 22-year-old Orson Welles as Lamont Cranston, with Frank Readick delivering the famous introductory line, "Who knows what evil lurks in the hearts of men? The Shadow knows!" accompanied by an ominous laugh and a haunting musical theme. The show emphasized the message that "crime does not pay" and captivated audiences with its themes of mystery, magic, and morality.