Endoscopy involves inserting a thin, flexible tube with a camera into the body to examine the interior of an organ. There are several types of endoscopes including rigid, fiberoptic, and video endoscopes. Endoscopy is used for both diagnostic and therapeutic purposes in various parts of the gastrointestinal tract. It allows direct visualization of the interior and enables procedures like biopsy, polyp removal, and management of bleeding. New techniques like capsule endoscopy, balloon enteroscopy, ERCP, chromoendoscopy, and endoscopic ultrasound have expanded endoscopy applications.