When I was growing up I absolutely loved the lavishly illustrated
Right at the beginning, Wexo notes that, "The story of dinosaurs really began when the first animals appeared on earth." In truth the story of dinosaurs could be extended backwards even further, to the last common ancestor of all life on earth, but it is still commendable that he has attempted to place dinosaurs in an evolutionary context. This first part of the book goes from single-celled organisms to the first land-dwelling vertebrates to the ancestors of the first dinosaurs. The delivery is fast and furious, but my only real complaint is that Wexo avoided using the actual word "evolution." Instead Wexo says organisms "develop" and "appear", which seems to be an attempt to tip-toe around the dreaded e-word.
While the background information is not entirely scientifically accurate (especially the discussion of the first land-dwelling vertebrates) it does help frame the question of "where dinosaurs came from." Dinosaurs did not appear out of nowhere but were the modified descendants of earlier organisms. The trouble is that by the time Wexo gets to the dinosaurs, relatively little time is spent on explaining how different groups of dinosaurs evolved or even when different kinds of dinosaurs lived. Theropods, armored dinosaurs, horned dinosaurs, and sauropods are all lumped together, and some non-dinosaurian marine reptiles are thrown in for good measure. The book then abruptly ends with no concluding section tying the lessons of the book together. Likewise, the fact that the book never discusses feathered dinosaurs or that birds are living theropod dinosaurs is a major flaw.
There are also a number of scientific mistakes within the book that would be sure to frustrate anyone with technical knowledge of paleontology and evolution. Then again, when I was a kid I had a whole library of similar dinosaur books and this will probably not be the one and only dinosaur book in the collection of today's young dino-maniacs. Maybe it will help paleontologists-to-be to graduate to more comprehensive books like Thomas Holtz's encyclopedia, Dinosaurs.