FEATURES, FACTORS, AND CHARACTERISTICS. History. Epidemiology. Ontogeny. Phylogeny and Animal Models. Upper Airway Anatomy. Physiology and Dynamics of the Upper Airway. Upper Airway Pathology. Control of Breathing in Sleep. Arousal From Sleep. Pathogenesis. Risk Factors. Familial and Genetic Factors. The Spectrum of Sleep-Disordered Breathing. ASSOCIATIONS AND CONSEQUENCES. Morbidity and Mortality. Central and Autonomic Nervous System. Cardiac Arrhythmias and Congestive Heart Failure. Hypertension and the Cardiovascular System. Endocrine Function and Glucose Metabolism. Obesity. Mood and Behavior. Sleepiness. Health-Related Quality of Life. Driving Risk and Accidents. Economic and Societal Impact