Synopsis: In the present Grant Ryals was a world-famous figure, the man who had mastered time travel, and who now was surrounded by the ravenous forces of commercial greed and by the man-eating appetites of "celebrity groupies", women who wanted to add him to their list of conquests at any price. In the prehistoric past Grant Ryals was the only human being on the face of planet Earth, walking through the great, trackless landscape of jungle, swamp, and sea that was Kansas millions of years ago, and facing the hugest and most hideous carnivorous creatures that had ever ruled the globe. In the present, Grant Ryals was fighting for his manhood. In the past, he was fighting for his life. And he did not know which was the more dangerous... (from the back cover of the Popular Library first edition)