Howarth's introduction and long running commentary beautifully complement the various excerpts, taken from Thoreau's Journal and published essays. Howarth did far more than cull accounts of Thoreau's adventures in the mountains of New England. He retraced, as far as possible, Thoreau's every step, and tells us what he saw, thus providing a sort of counter-text to Thoreau's, with some striking results. Howarth, for example, closely scrutinizes Thoreau's performance as a naturalist and outdoorsman, correcting his occasional errors (misnamed streams, false distances, etc.) and clearing up obscurities (he identifies the vague ""lumberer's drink"" that Thoreau ""sucked [from] the very teats of Nature's pine-clad bosom"" as black spruce-beer). More significantly, Howarth also contrasts the landscapes that met Thoreau's eyes with the same country 120-140 years later. Sometimes this is in a vein of muted protest, as when he describes the advance of crude commercialization in the White Mountains, sometimes more with an ironic shrug of plus ca change, etc. (Writing about Monadnock, Thoreau complained of crowds, litter, and minor vandalism; Howarth notes that 125,000 visitors a year now climb the mountain.) As concretely inclined as his great predecessor, Howarth fills readers in on how to duplicate Thoreau's hikes, even descending to details such as what highways to take or where to make reservations for overnight camping. Some of Thoreau's later reports are semi-arid catalogues of flora and fauna observed on the trail; but for most of the way, readers can enjoy the double good company of a major writer growing into his art and a fine critic-biographer-backpacker who puts him into lucid, sympathetic perspective.