This book demonstrates that nature is not, contrary to Rousseau and his contemporary environmentalist followers, in the least bit benign or peaceful, and that destructive urges are hard-wired deep into our genetic systems. Like James Q. Wilson's The Moral Sense, but in a darker and more popularized way, this book draws heavily on biological and anthropological evidence to show that human beings are not by nature isolated, self-interested individuals but have powerful natural inclinations toward social groups, and that much of the violence and cruelty that has characterized human history is rooted in competition between groups for status and domination.
The problem with this approach in explaining contemporary phenomena like religious fanaticism or ethnic conflict is that the sociobiological impulses described in the book are all mediated by factors like culture, social structure, institutions, law, and historical experience. It is the latter factors, rather than raw genetic impulses, that explain why Bosnia and not Lithuania has exploded in genocidal violence recently. Moreover, it is too facile to say that the impulse toward group identity is the basis for war and intolerance; it is also the basis for every positive aspect of human social life as well.