The Adventures of Jimmie Dale

He was a wealthy playboy by day, but at night put on a costume and became The Gray Seal, who enters businesses or homes and cracks safes, always leaving a diamond shaped, gray paper "seal" behind to mark his conquest, but never taking anything. He was just doing it for "the sheer deviltry of it" at first, but when a woman catches him she blackmails him to affect retribution on certain crime organizations. Dale's adventures first appeared in People's Magazine and then were collected into novels: The Adventures of Jimmie Dale (1917), The Further Adventures of Jimmie Dale (1919), Jimmie Dale and the Phantom Clue (1922), Jimmie Dale and the Blue Envelope Murder (1930), and Jimmie Dale and the Missing Hour (1935), with the serializations generally appearing the year before the novel version was published. (cover image courtesy of Piotr Bizior www.bizior.com)