The terrifying Tyransaurus rex. The tanklike Triceratops. Although they vanished from Earth millions of years ago, these and other extinct creatures remain endlessly fascinating. When Disaurs Lived takes young readers back in time for a fundamental introduction to six ancient reptiles and the world they ruled. Each title features dynamic illustrations of the featured beast and its prehistoric surroundings, set alongside simple text that touches upon the creature's growth, features, and likely behavior.