On the bright side, there is very good coverage of breathing affected by sleep disorders. Nineteen chapters, about 60% of the book, are devoted to the physiology, epidemiology, symptom picture, and major treatments of sleep-related disorders of respiration. Yet the novice reader is confronted with inconsistencies in both the diagnostic criteria of sleep apnea and the appropriate treatments. Most often the diagnosis is based on the number of respiratory events per hour of sleep, but this ranges from five to 15 apneas or apneas plus hypopneas. At other times the number and severity of the desaturation episodes are included, or the number of arousals from sleep. Of course, where the diagnostic line is drawn affects the epidemiologic rates of this disorder. As for the treatment, the opening statement is that either surgery or the use of cumbersome equipment are the present effective therapies. This is followed, however, by a chapter on the usefulness of oral appliances and the greater compliance with these appliances. Weight loss is mentioned as another effective treatment. There appears to be no clear consensus on the boundaries between normal and abnormal sleep-related respiration, and treatments are a matter of clinical judgment.