The third edition of the ASMBS Textbook provides a comprehensive update on the field of metabolic and bariatric surery. The updated table of contents is aligned with the American Board of Surgery’s Metabolic and Bariatric Surgery Focused Practice Designation (FPD) blueprint and will serve as the definitive study guide for this certification.  The third edition boasts 74 chapters covering the breadth of this field and includes sections on the disease of obesity, the physiologic changes that result from these operations, updated techniques and outcomes, the diagnosis and management of complications, reoperative surgery, the emerging endoscopic therapies, and quality improvement topics. There is also an expanded section on special and high-risk populations that will serve as a valuable resource for metabolic and bariatric surgeons, and the increasing use of weight loss drugs before and after surgery is reviewed. The book also includes test questions relevant to the FPD examination and for use in training programs, with selected video links and images that will represent the state-of-the-art techniques for metabolic and bariatric procedures.  The ASMBS Textbook of Metabolic and Bariatric Surgery, Third Edition will serve as a reliable reference for students, residents, fellows, and practicing surgeons, as well as integrated health colleagues in psychology, nutrition, and advanced practice providers.