The fact that some alternative health treatments are now covered by health insurance is proof that they have entered the mainstream. The second edition of this set is ''a one-stop source for alternative medical information'' containing more than 800 articles covering 150 therapies, 275 diseases and conditions, and 300 herbs and other remedies. Alternative health practitioners, educators, pharmacists, and medical writers wrote the alphabetical, signed articles. All entries have resource lists of books, articles, and organizations, and many are illustrated with black-and-white photographs. Sidebars with biographies of leaders in the field, such as Edward Bach, Deepak Chopra, and David Palmer, are a new feature. A photo gallery of color plates of medicinal plants appears in each volume. Many entries have sidebars containing glossaries of key terms.