THE ENCYCLOPEDIA OF DINOSAURS and other prehistoric life begins with an introductory section that provides an overview to understanding fossils, evolution, and prehistoric life. This is followed by the four main sections of the book, which cover the major groups of prehistoric animals – Fish and Invertebrates, Amphibians and Reptiles, Dinosaurs and Birds, and Mammals and their Ancestors. Each entry in these four sections covers a particular prehistoric animal or a group of such animals. An extensive reference section at the back of the book contains a fossil timeline, details of how paleontologists find and study fossils, and biographies of noted researchers.