Yellowstone and Grand Teton National Parks, while mostly noted for grizzly bears, elk, moose, and other large mammals, also host a high species diversity of butterflies, owing to the ecosystem's vast area of pristine habitat. Many of the nearly 120 butterflies described can also be found elsewhere in the Northern Rockies, making the book useful beyond the artificial borders of the public lands. Illustrated with color plates of each species, A Field Guide to Butterflies of the Greater Yellowstone Ecosystem also provides basic information on butterfly anatomy and natural history, as well as the proper way to "catch and release" butterflies—though with a stern reminder that netting butterflies is not permitted in the national parks.