What I like about these books is that they are small, about 4" by 8" but contain information on birds, wildflowers, reptiles, trees, animals, insects, and just about any other living thing you might want to identify in a particular area. They are about 450 pages long, so they are relatively thorough, and also have a front and end flap you can use to save your place. In addition, they contain information on the geology of the region, parks, and other scenic areas you might want to visit. Even have diagrams of the night sky.
As opposed to those folders with pictures of wildflowers you can buy in a lot of places, these books have a description for each item listing things like size, blooming seasons, where they can be found, and a description of leaves and flowers. Photos mostly also include leaves, which help in identification. Cost of each is $19.95.
There is one for California, also, but no nearby bookstores have it. Someday, I will also order the New England version if I go there.