Vagabonding by Rolf Potts. It’s a short, inspiring book. There’s not a lot of practical, detailed information in this book, but he does provide references to books, web pages, magazines, etc where there’s more information than you could possibly want. He keeps the links updated on his site (http://www.vagabonding.net ), where he also answers questions and writes occasional things. The book and site are both valuable resources for anyone looking into long term travel, especially on limited funds.