Sixteenth-century Parisians—lacking movies, television, and Angry Birds—would often amuse themselves by stepping out for a cat-burning. As Steven Pinker has written, a live cat would be lowered into a fire, where, howling with pain, it would roast until it was black, while les citoyens, along with kings and queens, would shriek with laughter. France has happily abandoned the practice, and such behavior is now unthinkable (with the occasional tragic exception). For Pinker, this is one example of a millennia-long decline in violence.

“We are probably living in the most peaceful moment of our species’ time on earth,” he wrote in The New Republic in 2007. His new book, The Better Angels of Our Nature: Why Violence Has Declined, explores this surprising trend in much greater detail. He will show how violence has declined at every scale, from wars and genocides to the treatment of children and animals, and explain the trends in terms of a struggle among competing components of human nature. For more information...