"Tarzan and the Madman" (Tarzan #23) by Edgar Rice Burroughs

The drums boom forth an incredible message from tribe to tribe-Tarzan, Lord of the Jungle, has become an enemy to all, stealing and enslaving their women...as well as the daughter of an English millionaire, who offers a princely reward for her recapture and Tarzan's death. Certainly her captor told Sandra Pickerall that he was Tarzan...but he also told her he was God...

Tarzan follows their trail with one thought in mind-to pursue and destroy the man who has stolen his name and made it infamous in the jungle world he loves.