Disclaiming the conventional belief that living matter reacts passively in the face of threats to its existence, Lovelock argues that the earth's living matter - air, ocean, and land surfaces - forms a complex system which has the capacity to keep our planet a fit place for life. Now reissued with an updated preface which discusses how Lovelock's predictions have already begun to hold true, Gaia has dramatically altered the way scientists view evolution and the environment.