Approximately 40 million people in the United States suffer from chronic long-term sleep disorders each year and an additional 20 million people suffer occasional sleep problems. This issue of Otolaryngologic Clinics presents to the otolaryngologist the most up-to-date clinical information on diagnosis and testing of patients with this disorder. Contents include:: Physiology of sleep apnea and sleep-disordered breathing; Interpretation of adult polysomnograms; Interpretation of pediatric polysomnograms; Home sleep studies; Diagnostic studies to evaluate the site of obstruction in obstructive sleep apnea patients; C-PAP for the treatment of sleep apnea; Surgery of the palate and oropharynx; Surgery for hypopharyngeal obstruction; Surgery for pediatric sleep apnea; Pre and Postoperative management of obstructive sleep apnea patients; Success and Failures in Treating Sleep Apnea Patients