By William J. Fritz and Robert C. Thomas. This guide explores the park's volcanic history while also delivering you to sites that have recorded the region's broad and deep geologic story, including petrified trees, mountain-sized blocks of rock that slid more than 50 miles in a massive debris avalanche, glacially carved peaks and valleys, and the Grand Canyon of the Yellowstone. This completely revised second edition reexamines the region using the latest scientific thinking and now includes full-color photos, maps, and diagrams. 2011. Softcover. 328 pages. 6" x 9"