The Shadow was an invisible avenger who had learned, while "traveling through East Asia," "the mysterious power to cloud men's minds, so they could not see him." This feature of the character was born out of necessity: time constraints of 1930s radio made it difficult to explain to listeners where The Shadow was hiding and how he was remaining concealed. Thus, the character was given the power to escape human sight. Voice effects were added to suggest The Shadow's seeming omnipresence. In order to explain this power, The Shadow was described as a master of hypnotism.

 

The Shadow has been featured on the radio, in a long-running pulp magazine series, in comic books, comic strips, television, serials,video games, and at least five motion pictures. It began on radio on January 5, 1932 and ended February 17, 1946 after 825 episodes.

 

"Who knows what evil lurks in the hearts of men? The Shadow knows!"