Book excerpt: Over the past twenty plus years clinicians have noted significant disorders of the lung, larynx, pharynx, nose, sinuses and middle ear that occur because of duo-denogastric refluxate (DGR) extending to these areas. While it has long been evident that gastric contents reaches the esophagus and will cause problems in the form of gastroesophageal reflux disease (GERD) the disorders of extra-esophageal reflux (EER) are increasingly causing morbidity to patients. Recently there have been basic and clinical studies indicating that other components of DGR cause damage to extra-esophageal structures. The combination of state of the art research and clinical presentations of EER make this book very valuable to those who investigate and manage patients.