Civilization rearranges nature for human convenience. Clothes and houses keep us warm; agriculture feeds us; medicine fights our diseases. It all works--most of the time. But key resources lie in the most hazardous places, so we choose to live on river flood plains, on the slopes of volcanoes, at the edge of the sea, above seismic faults. We pack ourselves into cities, Petri dishes for germs. Civilization thrives on the edge of disaster. And what...