In Edgar Rice Burroughs’ eighth Tarzan novel, ‘Tarzan the Terrible’, (1921) two months have passed since Tarzan learned that Jane, whom he thought to be dead, is alive. He tracks her to a hidden valley called Pal-ul-don which contains both prehistoric dinosaurs, and a lost civilization of hairless, tailed, human-like creatures. Jane, who is being held captive there by a German villain soon finds herself at the center of a religious power struggle and it is up to Tarzan to rescue his true love. First published as a serial in the Argosy Weekly, this novel contains one of Burroughs’ most thoroughly-realized Lost Civilizations.