Endoscopy brings visual diagnosis and minimally invasive therapy to the GI tract, marrying optics with therapeutic tools. This text provides detailed procedural guidance for upper and lower endoscopy, ERCP, and advanced interventions such as ESD and POEM, with step-by-step technique descriptions. Instrumentation chapters explain scopes, insufflation, electrosurgery, and accessories, while pre- and post-procedure sections cover patient selection, sedation, and recovery. Complication recognition and management are highlighted with checklists and pearls to reduce adverse events. Training resources include simulation protocols, competency milestones, and tips for building an endoscopy service. It’s tailored for fellows, endoscopists expanding their skillset, and endoscopy nurses.