An iconoclastic study in which social commentator and Time essayist Ehrenreich challenges accepted notions of why human beings wage war. In her tenth book Ehrenreich (The Worst Years of Our Lives, 1990, etc.) takes a multidisciplinary approach in her investigation of ""the feelings people invest in war and often express as their motivations for fighting."" She makes a thorough examination of a wide range of historical, psychological, sociological, biological, and anthropological literature to come up with her unique theory: that the accepted view that human beings engage in wars because of an innate aggressive, warlike instinct--especially in men--is untrue. Instead, Ehrenreich persuasively argues that the ""roots of the human attachment to war"" can be found in feelings and emotions that are imprinted on all of us due to events that took place many millennia ago, when our earliest ancestors spent most of their waking hours in fear of being devoured by predators. What Ehrenreich calls humankind's ""sacralization of war"" (the tendency to invest the emotional trappings of religious fervor in war) stems from the evolution of humans from prey into predators, the feelings engendered in ""a creature which has learned only 'recently,' in the last thousand or so generations, not to cower at every sound in the night."" The human predilection for war, as Ehrenreich puts it, can be viewed ""as a way of reenacting the primal transformation from prey to predator."" Also key was ""a global decline in the number of large animals, both 'game' and predators, for humans to fight against."" In making these original arguments, Ehrenreich challenges long-held theories of evolution and psychology promulgated by Darwin, Freud, and other scholars. Ehrenreich's work is convincing, at least to the general reader. Her ideas likely will be challenged by those whose theories she seeks to discredit.