The Adventures of Jimmie Dale by Frank L. Packard

Published in 1917, this novel introduced Jimmie Dale, a wealthy socialite who leads a double life as the Gray Seal, a reformed safecracker blackmailed into crime by a woman he's never met. An early template for the pulp-era gentleman vigilante, told in two parts.

Includes the full unabridged audiobook (LibriVox recording, ~19 hours) along with the ePub.