The Dinosauria (second edition) is the longawaited update of the 1990 volume of the same name (Weishampel et al. 1990a), which in the past fourteen years has become a fixture on the desks and shelves of dinosaur paleontologists and enthusiasts worldwide. In many ways, that first edition was the first of its kind (as the editors themselves noted; Weishampel et al. 1990b), presenting what was the only truly comprehensive, research-based guide to dinosaurs written by scientists. This second edition is faithful to the first in many ways. All of its good qualities are still apparent; some have been improved. Certain crimes and misdemeanors have been eliminated; a few still lurk the pages. It has also been updated to within an inch of what publishers will allow; indeed, some 2003 papers must have snuck in under the cover of editorial night. And at $95, this substantial hardcover volume is, in fact, a bargain. But really, you don’t need me to tell you this. The Dinosauria (second edition) is the kind of book that most paleontologists, or at least most vertebrate paleontologists, will buy. And they will not be disappointed for doing so, because this edition succeeds in the same ways as the first, and enjoys some new accomplishments as well. Nonetheless, a great deal of effort went into producing this book, and it deserves (or, if you prefer, is not excused from) a proper review.