For most of history, war, slavery, infanticide, child abuse, assassinations, pogroms, gruesome punishments, deadly quarrels, and genocide were ordinary features of life. But today, Pinker shows all these forms of violence have dwindled and are widely condemned. How has this happened? This groundbreaking book continues Pinker's exploration of the essence of human nature, mixing psychology and history to provide a remarkable picture of an increasingly nonviolent world.