Obstructive sleep apnea (OSA) in adults is a common disease, usually associated with cardiovascular disease and metabolic syndrome. Though involving many medical disciplines, it is often overlooked by physicians. In the past two decades, the population of obese people has greatly increased. As obesity is a major risk factor of OSA, it is possible that the incidence of OSA will rocket in the near future. Thus, it is necessary and important to educate physicians about OSA. The intention of the book Obstruc- tive Sleep Apnea in Adults–Relationship with Cardiova- scular and Metabolic Disorders is to provide physicians with the diagnostic and therapeutic strategies of OSA.