What draws our species to war? What makes us see violence as a kind of sacred duty, or a ritual that boys must undergo to become men? Here the author of Nickel and Dimedtakes a journey from the elaborate human sacrifices of the ancient world to the carnage and holocaust of 20th-century "total war." Ehrenreich sifts deftly through the fragile records of prehistory and discovers the wellspring of war in an unexpected place—not in a killer instinct unique to the males of our species, but in the blood rites early humans performed to reenact their terrifying experiences of predation by stronger carnivores.

"Illuminating…. It is a large step from the all-male hunting band to the U.S. Marine Corps. Ehrenreich plots the path, nevertheless, both passionately and persuasively."—Washington Post