" As creator Gibson tells it, the character evolved almost by accident. In 1930, Street and Smith—prolific producers of pulp fiction magazines—decided to try the new medium, radio, in an effort to boost circulation. Once a week a drama would be adapted from an upcoming issue of Detective Story. Adapter Harry Engman Charlot added the gimmick of the mysterious host, called him the Shadow, and left the link to the magazine somewhat tenuous. “Apparently,” wrote Gibson in his Shadow Scrapbook, “some listeners didn’t get this message clearly, because instead of asking about Detective Story Magazine, they wanted the magazine that told about the Shadow.” The answer was obvious—a new magazine, with the Shadow as its nucleus. Gibson, then a hustling freelancer whose acquaintances included magicians Houdini and Blackstone, was called in to help develop the character and get the new publication off the ground. "
― John Dunning , On the Air: The Encyclopedia of Old-Time Radio