The Adventures Of Jimmie Dale: An Adventure/Pulp Classic By Frank L. Packard!

Wealthy heir by day, at night Jimmie Dale dons a costume and becomes "The Grey Seal," daredevil safe cracker and footpad -- he never takes a thing, but leaves behind his mark, a grey seal of paper. When a woman catches him in the act her blackmail demands that he put his talents to use against criminal organizations!