Noninvasive Mechanical Ventilation is organized into 15 chapters; although Dr. Bach is listed as editor, he is also credited as the sole author of 8 chapters and coauthor of 5 more. The first two chapters contain introductory material covering the attributes of various disorders resulting in chronic ventilatory failure and the pathophysiology of ventilatory failure contrasted with oxygenation failure. This information does not present anything terribly novel for the pulmonary practitioner, and with respect to pathophysiology there are other chapters in other texts that are far more organized and clearly written. The third chapter covers the history of mechanical ventilation, and will be of significant interest to those of a historical bent. I was unsure of the purpose of the next chapter, entitled “Noninvasive Ventilation: Mechanisms for Inspiratory Muscle Substitution,” which did not seem to have a cohesive theme that could be described by its title. It starts out by making the point that neuromuscular disease patients supported by positive pressure ventilation via tracheotomy are often hyperventilated, and that their chronically hypocapnic state then interferes with any subsequent attempts at autonomous breathing. However, the mechanisms given are contradictory: the text seems to suggest that the patient’s inspiratory drive is increased, thus overtriggering the ventilator and resulting in hypocapnia, but also states that all of the patients studied “… were unable to trigger the ventilator.” I suspect he was making a case for these patients experiencing excessive dyspnea during weaning attempts due to their usual state of iatrogenically induced hypocapnia, but this was still difficult to discern after several re-readings. The rest of the chapter deals with various noninvasive patient/ventilator interfaces and why they work (much of which is repeated in later chapters) and concludes with a discussion of the putative benefits of maximal insufflations on lung and chest wall mechanics.