Murray Bookchin (1921–2006) was the originator and primary theorist of social ecology, a radical politics that insists on the social roots of environmental destruction. Over the course of his long life Bookchin constructed social ecology as a coherent framework encompassing ecological politics, nature philosophy, anthropology, revolutionary history, face-to-face democracy, and urban decentralism. In this pamphlet Janet Biehl traces the evolution of Bookchin’s eco-decentralism from the work of two earlier thinkers, Lewis Mumford and E.A. Gutkind.