James Lovelock is best known as the father of Gaia Theory, the idea that life on Earth is a self-sustaining system in which animals, plants, forests and sea life interact with the atmosphere, land and sea to maintain a habitable ecosystem. At least until humans came along. But as well as being a scientist, in his long life Lovelock was many other things: an environmentalist and inventor, an industrialist, NASA engineer and spy. Lovelock's life was a chronicle of twentieth century science, and somehow he seemed to have a hand in much of it. During the Second World War he worked at the National Medical Research Institute, where his life-long interest in chemical tracing began. In the 1960s he worked at NASA on a planned Mars mission. He worked for MI5 and MI6 during the Cold War. He was a science advisor to the oil giant Shell, who he warned as early as 1966 that fossil fuels were causing serious harm to the environment. He invented the technology that found the hole in the Ozone layer; the same technology that may have had military applications too. And all of this came together to shape his nascent environmentalism and to give shape to Gaia Theory - a theory that could not have been developed without the collaboration and inspiration of two important women in his life. Based on over eighty hours of interviews with Lovelock and unprecedented access to his personal papers and scientific archive, Jonathan Watts has written a definitive and revelatory biography of this fascinating, sometimes contradictory man.