By Mark C. Marschall. The official guide to hiking in the park, written by a Yellowstone backcountry ranger and published by the Yellowstone Association. Features descriptions and mileage for over 100 trails, including 45 day hikes. Detailed planning information including topographic maps, elevation profiles, and three dimensional views of major peaks. Spiral bound. Includes foldout map showing all trails and backcountry sites.