Ideas about dinosaurs are always changing.” This statement, made near the end of Kelsey’s book, represents its theme. Rather than presenting a series of facts as in most dinosaur books, the author informs readers about the up-to-date theories and ongoing investigations of internationally renowned paleontologists and scientists. Aided by such modern technologies as CAT scans and electron microscopes, these experts use comparisons to modern-day animals as well as deductive reasoning to revise theories and make new discoveries about dinosaurs. Thus, the reader follows the steps that a scientist takes to figure out if a fossil is a coprolite (animal dung) or whether an oviraptor was an egg robber, as was originally thought, or an egg protector.

This unique approach to the topic of dinosaurs is not the only thing that sets this book apart. The creative design and original photography attract the reader even before the text is explored. Each chapter is introduced by an impressive double spread with a large title and illustration, two questions that are answered in the chapter, and a profile of a dinosaur family in the form of a sidebar. In keeping with the investigative approach of the book, each profile lists attributes that can help readers identify members of a particular dinosaur group. The body of the text is written in a conversational tone with frequent comparisons to everyday objects (T. Rex teeth were as big as bananas). While these features make the information accessible, younger children might have difficulty with the mature vocabulary and sentence structure. This is an ideal book for 11-year-olds and up.