Murray Bookchin (1921-2006) was one of the most significant and influential environmental philosophers of the twentieth century. The founder of the social ecology movement, Bookchin was presenting and publishing foundational ideas about issues like air and water pollution, nuclear radiation, and the dangers of fossil fuels. He was a genuinely original and prescient thinker who was grappling with problems that we still face today-and proposing solutions for them-before most people realized those problems existed.