On Caprona, the Land that Time Forgot, all of the world's savage past still lives. Here are dinosaurs and flying reptiles, here are the most primitive of cavemen and the last of the Bronze Age barbarians. But there is one more secret that the claws and fangs and sharp-edged spears guard most of all. This is the story of the man who tried to find that final secret. When Bradley the adventurer dares to cross the last terrible barrier to the heart of Caprona, he enters a world of wonder, terror and danger beyond the imagination of any man - except the imagination of Edgar Rice Burroughs.