Through more than 75 meticulously hand-drawn illustrations, plus ten gorgeous gatefolds, experts from the world-famous American Museum of Natural History recreate the world of the dinosaurs as it was over 250 million years ago. Each gatefold presents a dinosaur-related subject, from the characteristics of the Triassic, Jurassic, and Cretaceous time periods to dinosaur classification using a cladogram. In addition, readers will accompany a paleontologist on an excavation and learn how they plan a dig!