Descriptions of 380 species include size, weight, color, markings, number of teeth, habitat, habits, and comparisons with similar species. Superb color illustrations and line drawings show 230 animals. Range maps as well as photos of skulls and drawings of animal tracks, dens, nests, and burrows round out the wealth of information given in "the best general guide to all of North America" (Peter Warshall, Whole Earth Review).