Many hikers on the Appalachian Trail take books as companions, in spite of the extra weight in their packs, but Ian Marshall carries the habit to new literary, ecological, and spiritual heights. In the more than twenty years he's been hiking the trail, Marshall, known on the AT as Evergreen, has practiced what he likes to call -an ecology of reading, - exploring America's past, its landscape and national experience, through literature inspired by places in the Appalachian chain: -a literary heritage, - he writes, -of interest to scholars and hikers alike, both seekers of a...