The Appalachian Trail covers 14 states, and over 2,000 miles. It stretches along the East Coast of the United States, from Maine in the north to Georgia in the south. It is famous for being the longest continuous footpath in the world. (Compare this with the Pennine Way, which is a mere 250 miles long.) It snakes through some of the wildest and most spectacular landscapes in America, as well as through some of its most poverty-stricken and primitive backwoods areas - Redneck country - Moonshine, Lil' Abner, there's bears in them thar hills. Remember the film Deliverance?

God only knows what possessed Bill Bryson, a reluctant adventurer if ever there was one, to undertake this gruelling hike. Perhaps it was just a long-held ambition to lose weight: he has lost two stone so far. As he recently wrote from the trail to his publisher:

'Speaking of vigorous exercise, boy have I just had some. Maine was a bitch. I want you to come back and walk it with me so that when you die if...