Dr. James Lovelock roposed the GAIA concept. Few ideas have ignited more contentious debate within the modern scientific community than James Lovelock's Gaia hypothesis -- the proposal that the Earth can be viewed as a superorganism with the capacity to regulate its internal environment. Lovelock, an atmospheric chemist employed in the 1960s by NASA, first proposed the Gaia concept to account for the anomalous composition of Earth's atmosphere relative to those of neighboring Mars and Venus. The peculiar mix of gases that envelope Earth and support life on the planet, Lovelock argues, is created and maintained by Life itself. The composition of the atmosphere, in turn, profoundly affects Earth's climate, which has remained favorable for life for at least 3.5 billion years. Lovelock's thesis, then, is that organisms have collectively acted throughout the history of the planet to make the global environment hospitable for the biosphere as a whole.