A really great, useable book. Identifying a raptor is rarely difficult if you see it well. This book will help you learn to do it when you don't see the bird well. When you devote 250 pages to just 23 species, you get to include a lot of information. But this isn't a book that's crammed with facts, figures, and field marks. The descriptions, line drawings, and photographs are intended to teach you how to tell these birds apart in the real world, where profile and silhouette usually matter more than detailed markings. And they work. Although the coverage is a little biased toward the eastern U.S., this book is invaluable for distinguishing all of the buteos, accipiters, eagles, falcons, and vultures regularly found in North America, except for a number of extreme-southern species. And even if where you live you have to deal with White-tailed Hawks and Hook-billed Kites, and hope someday to find a Crane Hawk, at least this book will help you to become expert with the more widespread species.
An excellent guide to the "holistic" method (shape, manner of flight, general impression and behaviour etc.) of raptor identification, used by most hawkwatchers since hawks in flight are generally too distant for identification by field marks, color etc.