Part I Obesity -- 1 Historical background: from the past to present -- 2 Incidence and prevalence of Obesity. -3 The Pathophisiological of Obesity -- 4 Obesity-related Comorbidities -- 5 Hypogonadism and Obesity -- 6 The microbiota organ and bariatric surgery -- Part II Surgery of Obesity -- 7 The "Bariatric Multidisciplinary Centre" --  8 Metabolic surgery -- 9 Diabetes Surgery -- 10 The role of laparoscopy in Bariatric Surgery -- 11 Anesthesia in Bariatric Surgery -- 12 Fast Track in bariatric Surgery- Safety, quality, teaching aspects, logistics and cost-efficacy in 8000 consecutive cases -- Part III Surgical Treatment -- 13 Indications For Bariatric Surgery -- 14 Endoscopic treatment: Intragastric Balloon -- 15 Endoscopic Treatment: New technologies -- 16 Adjustable Gastric Banding -- 17 Laparoscopic Roux-en-Y Gastric Bypass: Technical Aspects, Clinical Management and Outcomes -- 18 Laparoscopic Sleeve Gastrectomy -- 19 Bariatric and Metabolic Mini-invasive Surgery: Principles and Technical Aspects -- 20 Laparoscopic Duodenal Switch -- 21 Laparoscopic Gastric Plication -- 22 Revisional Surgery: Gastric Banding failure -- 23 Revisional or conversion procedures for Roux-en-Y Gastric Bypass Failure -- 24 Revisional Surgery: Biliopancreatic Diversion failure -- 25 Emergencies in Bariatric Surgery: Highlights for the General Surgeon -- 26 Emergencies in bariatric surgery: Internal hernia -- Part IV Outcomes -- 27 Nutrition Outcomes -- 28 Long-Term Follow Up after Bariatric Surgery.