Book excerpt: Health Online turns a computer into your most important health tool. For newcomers, it makes going online easy by explaining e-mail and showing what's on the big commercial online services. Later chapters explore Internet mailing lists, newsgroups, and World Wide Web pages. Even online veterans will benefit from the book's listings of hundreds of health resources, especially self-help support groups. Health Online finds the healing power of electronic networks not in technology or data, but in the worldwide community of people helping each other.