BOOM! A giant meteor blasts an enormous crater into Earth's surface, causing the end of what scientists call the Age of Dinosaurs. In this newly revised edition of a perennial popular book, Gail Gibbons presents the most recent theories about the history of dinosaurs, along with amazing facts about dinosaur discoveries. Dig in to learn about the Triassic, Jurassic, and Cretaceous periods and many of the dinosaurs that lived during those times. With plenty of facts to satisfy aspiring paleontologists, Dinosaur Discoveries brings to life these magnificent creatures that lived on Earth for about 165 million years. Updated information includes new discoveries about dinosaurs¿ physical traits and their uses, from bony frills and hollow nose crests to armor plates and whip-like tails.