Gastroenterology is a specialized field of medicine, which focuses on the diseases of the gastrointestinal (GI) tract or the digestive system. The GI tract is responsible for the digestion of food, absorption of nutrients and removal of wastes from the body. The diseases treated under the scope of gastroenterology are ulcers, acid reflux, hepatitis C, jaundice, pancreatitis, colon cancer, hemorrhoids, etc. The diagnosis of most of these conditions can be done non-surgically with the help of colonoscopies, endoscopic ultrasounds, sigmoidoscopies, liver biopsies, double balloon enteroscopies, endoscopic retrograde cholangiopancreatography, etc. Certain endoscopic procedures can also be used for the removal of polyps, esophageal and intestinal dilation, and for stemming blood loss, among others. The aim of this book is to present researches that have transformed the discipline of gastroenterology and aided its advancement. It traces the progress of this field and highlights some of its key aspects. It is an essential guide for both academicians and those who wish to pursue this discipline further.