This document discusses the anatomy, physiology, and motility disorders of the esophagus. It begins by describing the anatomy of the esophagus, including its layers, blood supply, drainage, and normal narrowings. It then discusses the physiology of swallowing and peristalsis. Several esophageal motility disorders are described, including achalasia, diffuse esophageal spasm, and scleroderma-related disorders. Diagnosis involves history, imaging like barium swallows, and manometry studies. Treatment aims to relieve obstruction and includes medications, botulinum toxin injections, dilation, and surgery. Barrett's esophagus, a complication of longstanding reflux, is also summarized.