"We eat, drink, worry and smoke too much, and we drive too fast" (Robert R. Whalen, quoted in reference 1). But there is more to say about health psychology, much more, to the extent of three thick volumes, of which the book reviewed here is the first. The American Psychological Association, the book’s sponsor and publisher, has reason to be well pleased with this encyclopedic treatise, for it signifies the maturity of health psychology. As of 2003, in its 25th year, the Division of Health Psychology of the American Psychological Association has grown to 2,800 members. Health psychology, which might be roughly defined as the sum of the activities of psychologists who work in the health care system, includes a remarkable diversity—behavior change programs for smoking, obesity, and stress; support groups for victims of chronic illness and their families; nonpharmaceutical treatment to help patients cope with chronic pain; cognitive and emotional retraining following stroke; assessment of candidates for sex reassignment surgery, back surgery, and sterilization; and much more.