The Earth, James Lovelock proposes, behaves as if it were a superorganism, made up from all the living things and from their material environment. When he first sketched out his brilliant Gaia theory in the 1970s, people around the world embraced it; within a short time Gaia has moved from the margins of scientific research to the mainstream. James Lovelock argues that such things as the level of oxygen, the formation of clouds, and the saltiness of the oceans may all be controlled by interacting physical, chemical, and biological processes. He believes that "the self-regulation of climate and chemical composition is a process that emerges from the tightly coupled evolution of rocks, air, and ocean - in addition to that of organisms. Such interlocking self-regulation, while rarely optimal - consider the cold and hot places of the earth, the wet and the dry - nevertheless keeps the Earth a fit place for life". The New York Times Book Review has called his arguments in favor of Gaia "plausible and above all illuminating". Now, in an updated paperback edition, fully revised, the author amplifies his account of how Gaia works with descriptions of new fields of research that have been opened by this pathbreaking concept.