This book introduces young children to the dinosaur, tyrannosaurus rex, whose name means "tyrant lizard king". The tyrannosaurus rex lived throughout North America and became extinct over 65 million years ago. It was one of the largest dinosaurs that ever lived. It was bigger than a school bus. It was a carnivore, had a big mouth, and could eat up to 500 pounds of meat in one bite. The tyrannosaurus rex had very strong legs and was able to run more than 25 miles per hour.