Endoscopic access to the small intestine has for a long time presented a challenge to physicians. Although capsule endoscopy can provide an endoscopic image from the entire small intestine, neither biopsy nor endoscopic treatment can be performed with it. In order to make more definitive diagnoses of abnormal findings detected by capsule endoscopy, a new system incorporating greater insertability and maneuverability is required. Double-balloon endoscopy, which enables endoscopic observation of the entire small intestine, represents such a new system. The chapters of this book describe the principles, insertion technique, and clinical applications of double-balloon endoscopy, which will become the gold standard of enteroscopy and may well eliminate the need for intraoperative enteroscopy in many patients. As such, this book will provide an invaluable source of reference for all practitioners working in the field.