James Lovelock was born July 26, 1919, in Hertfordshire, England, and is an independent scientist, inventor, and environmentalist. He invented the electron capture detector for gas chromatography—an instrument whose exquisite sensitivity has subsequently been central to several important environmental breakthroughs. For example, during the 1960s it enabled the documentation of widespread dissemination of harmful and persistent pesticides like DDT, and later the technique was extended to the polychlorinated biphenyls (PCBs). Lovelock himself used the technique to chart the ubiquitous presence of chlorofluorocarbons (CFCs). He also developed instruments for exploring planets other than our own, including those aboard the two Viking craft that went to Mars in 1975.

Lovelock is best known for the Gaia hypothesis, which presents the Earth as a carefully interconnected, self-regulating cybernetic “super ...