"Humanity" is ultimately little more than a compendium of conventional wisdom. Glover offers little clear explanation of why these atrocities happened, content with describing them as the outcome of a disastrous meeting between the darker aspects of "psychology" and new destructive technologies. Even his moral lessons are confusing yet predictable; he observes that having a strong sense of identity can help people resist committing terrible acts, yet that at times a strong identity can actually be forged in the commission of horrors. Religion plays a minor role in his analysis; problems of character are considered in terms of identity rather than faith. More attention to the history of these terrible regimes--rather than simply repeating how terrible they were--would have deepened not only the historical but the moral weight of Glover's book.