Befitting its intended audience of nonsleep specialists, the sections on obstructive sleep apnea and narcolepsy are the most encyclopedic, since these are two of the most commonly encountered disorders. Douglas sets out by outlining the historical perspective, etiology, and mechanism, then fleshes out his descriptions with clinical features, the techniques of diagnosis, and treatment options. The narcolepsy section includes a short, but easily understood explanation of the genetics of narcolepsy, including recent research into hypocretins, as well as human leukocyte antigen typing. Clinicians should be particularly pleased by Douglas’ section on treatment of obstructive sleep apnea syndrome. He presents a cogent discussion of how continuous positive airway pressure therapy should be implemented, as well as providing useful information regarding predictors of compliance, and stressing the need for adequate follow-up care after continuous positive airway pressure therapy is prescribed. I must say that his statement that “We … no longer record sleep during [CPAP] titration studies” is bound to be a controversial point for most practicing sleep specialists, although he does take care to defend his position by pointing out how sleep can be monitored, albeit less definitively, without EEG recording. His discussion of surgical therapies makes references to his prior detailed discussion of the pathophysiology of the upper airways. The author is also careful to discuss how our understanding of the benefit of certain surgical procedures for obstructive sleep apnea is hampered by the relative lack of carefully conducted randomized studies.