"Whatever we once thought Nature was–wildness, God, a simple place free from human thumbprints, or an intricate machinery sustaining life on Earth–we have now given it a kick that will change it forever. Humanity has stepped across a threshold. In his free-ranging and provocative book, Bill McKibben explores the philosophies and technologies that have brought us here, and he shows how final a crossing we have made." –James Gleick, author of Chaos