Solly Zuckerman's early life in South Africa left him with a lifelong concern for the natural world. His mother, "an overpowering taskmaster," bred in him the habit of questioning established wisdom. These pressures, having first made him an academic scientist, carried him, amazingly, into the higher reaches of Government both in Britain and America. No other foreigner would ever have been invited to attend meetings of the President's Science Advisory Committee. He advised particularly on strategy of bombing, the peril of nuclear weapons, and the hazards caused by human numbers to the land, water, and air on which we all depend.