Scientist, author, and Earth-dweller, explores the many potential natural and man-made catastrophes that could change life as we know it, or erase us from the face of the Earth. Natural properties and laws might change at any time, rendering life on this planet--or anywhere in the universe--impossible. But the disasters that are most imminent are in our power to control--technology, nuclear warfare, pollution... Natural forces far more powerful than man might destroy us. Or they may have nothing to do with bringing about the end.