Most people, when they hear the word anarchy, picture a window being broken. This is unfortunate, because the word was meant to describe something quite different—a society without rulers, not a society without order. The two are easily confused only by those who suspect, in their hearts, that without a uniformed person standing nearby they would immediately bite their neighbor.

Peter Kropotkin, a Russian prince who renounced his title and most of the comforts that came with it, devoted his life to a stranger proposition. He claimed, with the patience of a naturalist and the stubbornness of a man who had observed too many wolves and Siberian villages to believe otherwise, that cooperation, not competition, is the principal engine of evolution and the natural form of human society. Mutual aid, he argued, was not a charity invented by saints but a feature installed in living things by the long apprenticeship of survival.

This book takes that quietly radical idea and follows it through biology, neurochemistry, history, and the strange new architecture of the digital age. It examines why the human body operates without a president, why power tends to select for its worst possible occupants, and why institutions designed to help us seem to dissolve, on contact, the very impulses that make help possible. It looks at communities that tried to live by Kropotkin's principles—some that vanished, a few that quietly endured—and at the modern phenomena, from open-source software to encyclopedias written by strangers, in which mutual aid keeps reappearing under different names.