The esophagus is a tubular structure spanning from the posterior pharynx, through the thorax, and terminating in the stomach. It arises from endodermal foregut tissue. Its submucosal muscular layers are initially striated, transitioning to smooth muscle in more distal areas. Due to the distance in the body it traverses, the esophagus derives its blood and nerve supply from several structures. The role as a conduit from mouth to stomach necessitates secretory and barrier functions, as well as sphincters for protection from anterograde flow. Various modalities of esophageal test exist, ranging from fluoroscopy, to invasive endoscopy capable of obtaining tissue samples, to probes that detect pH and muscle tone, all of which play roles in identifying various pathologic processes. This review contains 12 figures, and 22 references. Key words: abdomen, endoscopy, esophagography, esophagus, impedance, lower sphincter, manometry, upper sphincter