"The Appalachian Trail, a thin ribbon of wilderness running through the densely populated eastern United States, offers a refuge from modern society and a place apart from human ideas and institutions. But as environmental historian and thru-hiker Sarah Mittlefehldt argues, the trail is also a conduit for community engagement and a model for public-private cooperation and environmental stewardship. In Tangled Roots, Mittlefehldt tells the story of...