December 13, 2007


Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages. By Thomas R. Holtz, Jr., Ph.D. Illustrated by Luis V. Rey. Random House. $34.99.

      If you know someone who is serious about dinosaurs – really interested in what they were, how they lived, and what we know and don’t know about them – you can scarcely find a better gift for him or her than this hefty, scientifically accurate, meticulously researched, lavishly illustrated volume. Thomas R. Holtz, Jr., a leading authority on tyrannosaurs and the founder and director of the Earth, Life & Time Program at the University of Maryland at College Park, here combines his own knowledge with that of 33 other top paleontologists to present a book about dinosaurs that is truly…well…encyclopedic.

      Younger children will want to start with the pictures: Luis V. Rey is one of the foremost dinosaur illustrators working today, and what he shows is absolutely marvelous – and in line with the best science currently known. It is also often very surprising. For example, his drawing of what Deinonychus – believed to be one of the smartest dinosaurs – could have looked like makes the creature’s head resemble that of a huge turkey, but with numerous super-sharp protruding teeth. Fanciful? Only to an extent: there is no way to know what soft tissues coated dinosaur skulls, since soft tissue does not fossilize, so this carnivore could have looked much like this – or not like this at all.

      It is the combination of carefully marshaled knowledge with free-ranging speculation that makes Dinosaurs such a fascinating book – and not only in the illustrations. The chapter on “Avialians (Birds),” for example, begins by explaining that “to modern scientists, an animal is a dinosaur if it is a descendant of the most recent common ancestor of Iguanodon and Megalosaurus. …[O]ne of the most important discoveries in paleontology of the pasty forty years is that birds are descendants of the most recent common ancestor of Iguanodon and Megalosaurus. In other words, birds are dinosaurs!” This leads to a discussion of flight and feathers (wing and tail), and an aside that is as interesting as anything in the chapter’s main argument: “[S]ome people mistakenly think that marine reptiles like plesiosaurs and ichthyosaurs were ‘seagoing dinosaurs.’ Others say that there were no marine dinosaurs. Both groups of people are wrong!” Holtz, of course, then goes on to explain why.

      Even these short excerpts from the text show that this is a plainly written but not simplistic book, rife with exclamation points but well grounded in the findings of modern scientists. The contributions by people other than Holtz himself tend to be more soberly written, but each takes up only a page and deals with a specific subject. Readers interested in a particular focus will find these sections fascinating; others can easily skip them. What no one should skip are the information on finding, classifying and assembling dinosaur fossils; the illustrations showing just how big various dinosaurs were; the “cladograms” showing the relationship among different dinosaurs of similar types; and the wonderfully speculative pictures showing how dinosaurs may have lived, reproduced and interacted. Would-be paleontologists get a fantastic bonus at the end: a multi-page dinosaur genus list in which Holtz tries to arrange all known dinosaurs into appropriate groups. New discoveries of dinosaur species continue to happen regularly – the very recent discovery of a dinosaur that apparently ate low-lying vegetation the ways cows do today occurred too late to be included in this book – so the end-of-book list is certainly not graven in stone; nor are this book’s chapters the last word on anything, since this field is ever-expanding. But Holtz provides such a firm grounding in the world of dinosaurs that an interested reader could certainly use this book as the basis for a long-term study. Or just read the book for fun – it’s equally good, and equally fascinating, on that basis.

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