The evaluation, including history, examination and testing, are detailed with clinical examples; Treatment options, including Positive Airway Pressure, Mandibular Advancement Devices and Surgical Treatments are discussed with regard to efficacy, patient selection and appropriate follow-up; and an extended section focuses on the evaluation of the sleepy or fatigued patient, a group frequently seen by otolaryngologists with etiologies possibly due to causes other than obstructive sleep apnea.