As Guest Editor, Dr. Glenn Furuta has assembled an extraordinary group of highly accomplished individual players-pediatric and adult gastroenterologists, endoscopists, and surgeons, pathologists, immunologists, and allergists - to produce a state-of-the-art issue devoted to Eosinophilic Esophagitis. This disease is complex, and in its varying presentations in children and adults, may have more than one pathogenesis. One thing is certain: eosinophilic esophagitis is an important disease that causes considerable morbidity in those afflicted and is a major cause of esophageal symptoms, particularly dysphagia. Eosinophilic esophagitis is increasing in frequency like bronchial asthma, to which it has been compared.The relationship of eosinophilic esophagitis to gastroesophageal reflux disease remains poorly defined in some cases. Chronic eosinophilic esophagitis seems to lead to fibrosis in some patients, and eosinophilic esophagitis has been linked to the Schatzki ring long associated with hiatal hernia and GERD. These issues, as well as a strong emphasis on current approaches to diagnosis and therapy are presented.