Douglas K. Rex, MD, MASGE, is a Distinguished Professor Emeritus at Indiana University School of Medicine and a full-time clinical gastroenterologist at Indiana University Hospitals. He has authored more than 250 original research papers, 60 book chapters, 220 invited papers, 60 editorials and 40 guideline papers. He is a Past President of the American College of Gastroenterology and Past President of the American Society for Gastrointestinal Endoscopy. Dr. Rex’s clinical interests are in endoscopy, particularly colonoscopy. He has the largest experience in endoscopic resection of large colon polyps in the United States and the world’s largest experience in completing colonoscopy in patients with previous incomplete colonoscopy. Dr. Rex manages patients at high risk for colon cancer including those with Lynch syndrome and polyposis syndromes. He also manages upper GI disorders, including Barrett’s esophagus.