LeapReader Leap and the Lost Dinosaur Book. Explore the prehistoric world! Meet more than 25 dinosaurs, and discover that science is everywhere as you travel through the eras to bring about a dinosaur family reunion. Learn about over 25 different dinosaurs. Discover what they liked to eat, when they lived and more! Get an early introduction to palaeontology and fossil classification. Explore the prehistoric time line, from the Triassic to Cretaceous periods. Age from 4 years.