Wow! Now that's a birding book! I picked this up while perusing the shelves at the gift store of a wildlife refuge. It had decent-sized pictures of a warblers and detailed descriptions so I brought it home with me. Once I started looking through the book, it's even better than I thought.
The book starts with terminology, an explanation of how to use the book's key, and detailed discussion of important markers you should pay attention to for identification purposes, including various parts of the anatomy, behavior, and sonograms for bird calls.
There are then multiple pages comparing the birds from different angles (the head, the tail, the side, from below, from an angle) and a "quick finder" which includes pictures of birds grouped by locale and time of year for a rapid look-up, followed by more sonograms. (I'm not going to lie, sonograms don't do much for me, but this book gives an excellent explanation and comparison for those learning and for those who benefit from them.)
Then we get into the reviews of the individual birds. There are easy to read symbols for the bird's location on the map, location in the environment (on the ground, high in the trees, etc.), any pertinent behavioral identifiers (tail wagging, etc.), basic color markings/tail appearance, and body shape at the top. Each bird is then shown and described over several pages worth of information with three larger photographs on the first page, followed by multiple smaller photographs highlighting certain markers you should take note of (location, food color, tail color, etc.), similar species, and other useful identification notes. There are also sonograms for male/vocal birds and another large picture to finish at the end of the bird's section. The birds are divided by sex if they are sexually dimorphic, so that you get multiple pages of the male chestnut-sided and then you get just as thorough a look at the female chestnut-sided. They also do this for birds who have both a "bright" and "drab" appearance, so that you get good images and explanations for identification on all the warbler presentations you might see in the wild. The end wraps up with non-warbler look alikes to be aware of, a quiz, and then information on how the birds appear and behave in flight.
I'm one of those people who needs photographs in bird books - drawings, no matter how detailed, don't work for me. I think this book does an excellent job of showing both drawings and photographs by using the advantages of both. Photographs are used as much as possible so that you are looking at real birds with the general and detailed explanations and in the comparisons, whereas drawings are kept to the more basic images: the general color pattern (no details, just yellow top, pale bottom, etc.), the general bird shaped (as a silhouette), and the appearance of the underside of the tail.
The book is a bit chunky and big for taking out in the field but that's a result of how thorough it is, so I think that's a very forgivable offense. I need someone to write sparrow and bird of prey books like this.