Discover the world of dinosaurs in this essential pocket guide to the prehistoric world. Learn about more than 150 prehistoric animals, including the sea-dwelling Plesiosaurus, the flying Pterodactylus, and the fierce Allosaurus. Creature profiles fill you in on those fascinating details needed to impress, such as which dinosaur has the thickest skull, who was the brainiest, and which dinosaur had more than 1,500 teeth.