We Homo sapiens can be the kindest of species and also the most vicious. What occurred during human evolution to account for this paradox? And how were the acquisition of language and the practice of capital punishment determining factors in the rise of culture and civilization? In the last 250 million years, humankind became an increasingly peaceful species in daily interactions even as its capacity for coolly planned and devastating violence remains undiminished. In tracing the evolutionary histories of reactive and proactive aggression, biological anthropologist Richard Wrangham persuasively argues for the necessity of social tolerance and the control of the savage divisiveness still haunting us today.