Both picture book and field guide, Arnosky’s 100th book shows how the shape and pattern of animal tracks reveal the identity and activity of the track maker. Clear, accurate drawings of tracks and trails pair with full-page paintings of North American animals from anhinga and white-tailed deer to cottonmouth moccasin and white ibises. He includes both large wild animals—bear and American buffalo—and small creatures whose tracks might be found in a back yard—cats, dogs, rabbits and mice. Four foldout pages show tracks of animal families—deer, other hoofed animals, felines and canines—life-size for easy comparison. A few paragraphs of gentle text introduce each family, pointing out identifying details, comparing them and adding information about the pattern of their tracks. Both attractive and informative, this is a splendid example of Arnosky’s skill at making natural history come alive for young readers and listeners as well as their parents. This slim, though oversize, package will spur aspiring nature detectives to do some tracking of their own. (table of contents) (Picture book/nonfiction. 6-10)