The author afterwards revised and expanded the text, in which form it was reissued as Thongor and the Wizard of Lemuria, first published in paperback by Berkley Books in 1969.

The tale of Thongor of Valkarth, barbarian warrior in the prehistoric continent of Lemuria, who becomes humanity's champion in their pivotal struggle against the Dragon Kings who had previously dominated the world.

He pictures the lost continent of Lemuria as a prehistoric kingdom located in the Pacific Ocean during the ice age, where Mesozoic wildlife persisted after a cataclysm wiped them out from the rest of the world.

An intelligent race of reptilian humanoids, which evolved from dinosaurs, once reigned supreme over Lemuria in a vast empire, before being driven off by barbarian tribes who invaded the continent via a land bridge.

The Thongor series relate the struggle of the titular protagonist as he unites the various tribes into a single army and complete his overthrow of the "dragon kings".