"The Natural History of Pennsylvania" is a unique, comprehensive guide to the nature of Pennsylvania. There are more than 400 full-color photographs, maps and illustrations covering everything from bears and beavers to snakes and spiders to weather and wildflowers. Learn about the state's geology, its endangered species and its rivers and mountains. Find out how it was shaped by the ice age and the movement of the continents. Learn about the first human residents. There are identification pages, with photos, of the common birds, butterflies, trees and wildflowers. And there's a month-by-month calendar showing when events in nature happen in Pennsylvania.