Vagabonding is a how-to guide on the practical and philosophical elements of long-term travel.
As a experienced independent traveller, I didn't find a lot that was new to me. I felt that much of the contents I could have written myself. What Potts does provide is a lovely writing style (also see his old salon.com column), a keen insight, some good thoughts on the philosophy of travel and a solid set of materials and references.
A good book for someone tempted by the idea of long-term independent travel, but needing a push to take the plunge.