Gastroenterology is a branch of medicine that studies the functioning of the digestive system and the diseases related to it. Diseases affecting the internal organs from mouth to anus, along the alimentary canal are the areas of focus in this field. Physicians or specialists in this field are known as gastroenterologists. The techniques and medical procedures used by a gastroenterologist to diagnose and treat gastrointestinal diseases include endoscopy, colonoscopy, liver biopsy and endoscopic ultrasound. Endoscopy is one of the most common procedures used in the treatment of gastrointestinal diseases. In this procedure, an endoscope is used for the purpose of examining the interior of a hollow body organ. This book provides comprehensive insights into the field of gastrointestinal medicine. It consists of contributions made by international experts. It will help the readers in keeping pace with the rapid changes in this field.