Following several early 1930s incarnations of the Shadow as a mere narrator of an anthology of crime stories, the Shadow as a character debuted in his own self-titled show in 1937. The lead was played by Orson Welles for about a year, then by Bill Johnstone until 1943. The show would eventually run for 25 years, a truly amazing feat. At its peak, The Shadow could boast a listenership of 15 million a week, and it almost single-handedly was responsible for creating a new era of pulp magazine superheroes.

The Shadow's alter-ego was Lamont Cranston. He was wealthy, knowledgeable about science, and he was a master of other people's minds, relying on mysterious powers he had picked up somewhere in his travels in the equally mysterious far east. The Shadow was straightforward in his sense of morality, however. He believed in right over wrong, in protecting the innocent, and in punishing the guilty.

Cranston's friend and companion, the lovely Margo Lane, was the only person who knew the connection between Cranston and The Shadow. Together they dealt with the most evil of characters, the most fiendish of plots. The Shadow was not squeamish about dispensing justice. He obtained confessions using intimidation and torture, then cackled his signature eerie laugh as the guilty was taken away in custody.

Listeners of The Shadow can most ably remember the signature introduction of each show: Who knows…what evil…llllurks…in the hearts of men?…The Shadow Knows!" Equally memorable was the show's closing line: "The weed of crime bears bitter fruit…crime does NOT pay!…The Shadow knows!"