The Gaia hypothesis emerged from two interpenetrating traditions, the mechanist and the organicist, with the former tending to reductionism and the latter to holism. While mechanist James Lovelock is the acknowledged father, he collaborated with the organicist Lynn Margulis in the early 1970s when the first papers appeared in the scientific literature. Both continued to be active in Gaia-related conferences until Margulis’s premature death in late 2011. In a very readable exposition, Michael Ruse succeeds brilliantly in tracing the philosophical roots (...) of this concept continuing in the histories of modern geology and biology to its formulation in the late twentieth century.This is Lovelock and Margulis’s definition of the Gaia hypothesis quoted in this book: “We conclude from the fact that the temperature and certain other environmental conditions on the earth have not altered very much from what is an optimum for life on surface, that life must actively maintain these conditions”. (shrink)