Andrew R. Block, PhD, received his bachelor's degree from Haverford College and his doctorate from Dartmouth College. He is a board-certified clinical health psychologist and fellow of APA Division 38 (Health Psychology). He has worked for more than 2 years with the Texas Back Institute in Plano, Texas, and, before that, with the Spine Institute in Carmel, Indiana. He specializes in presurgical psychological screening and perioperative treatment of candidates for spine surgery and pain control procedures (implantable stimulators and pumps), as well as candidates for bariatric surgery. He serves on the Conservative Care Committee and the Clinical Outcomes Committee of the North American Spine Society. Dr. Block has many peer-reviewed research publications in the areas of chronic pain and presurgical psychological screening, beginning in the 97 s. He has written two books, most recently The Psychology of Spine Surgery, of which he was lead author. He was also the editor-in-chief of the Handbook of Pain Syndromes: Biopsychosocial Perspectives. This is his fourth book.   David B. Sarwer, PhD, is professor of psychology, Departments of Psychiatry and Surgery, Perelman School of Medicine, University of Pennsylvania, and director of clinical services, Center for Weight and Eating Disorders. He received his bachelor's degree in 99 from Tulane University, his master's degree in 992 from Loyola University Chicago, and his doctorate in clinical psychology in 995 from Loyola University Chicago. Dr. Sarwer's research interests focus on the assessment and treatment of obesity. He is principal or coprincipal investigator on several grants from the National Institutes of Health, investigating the psychological and behavioral aspects of obesity and, more specifically, bariatric surgery. Dr. Sarwer is also a consultant to the Edwin and Fannie Gray Hall Center for Human Appearance, University of Pennsylvania Medical Center, where he conducts research on the psychological aspects of cosmetic and reconstructive surgery. Clinically, Dr. Sarwer is the director of the Albert J. Stunkard Weight Management Program and is actively involved in the Bariatric Surgery Program, Perelman School of Medicine, University of Pennsylvania. He conducts behavioral and psychological evaluations of patients before surgery and treats individuals with eating or other psychological concerns after bariatric surgery. Dr. Sarwer also provides psychotherapeutic treatment to people who have body dysmorphic disorder or other appearance concerns.