Tom Thwaites is a preeminent authority on hiking the trails of Pennsylvania. An ardent trail builder and maintainer, he is a past president of the Mid-State Trail Association and an active member of the Keystone Trails Association, the Appalachian Trail Conference, the Sierra Club, and the American Hiking Society. He is the author of Explorer's Guide 50 Hikes in Western Pennsylvania, Explorer's Guide 50 Hikes in Central Pennsylvania, and Explorer's Guide 50 Hikes in Eastern Pennsylvania. He lives in State College, Pennsylvania.