This issue of Otolaryngologic Clinics of North America, devoted to Obstructive Sleep Apnea, is guest edited by Dr. Mark A. D'Agostino. Articles in this outstanding issue include: Pediatric Sleep Apnea; Skeletal Procedures for Obstructive Sleep Apnea; Nasal Obstruction and its Role in Obstructive Sleep Apnea and Nasal procedures; Sleep Testing; Drug-induced Sleep Endoscopy; PAP Therapy for Obstructive Sleep Apnea; Palatal Procedures for Obstructive Sleep Apnea; Oral Appliances for Obstructive Sleep Apnea; Obstructive Sleep Apnea Overview and Economic Impact of Untreated Obstructive Sleep Apnea; Genioglossal Advancement, Hyoid Suspension and Tongue Base Radio Frequency for Obstructive Sleep Apnea, Endoscopic Partial Midline Glossectomy; Robotic Partial Glossectomy for Obstructive Sleep Apnea; Upper Airway Stimulation Therapy.