This is a great book about preparing for short-term societal or environmental crises - how to conserve water when the water's not running (after a hurricane, say), how to stay warm and safe when the ice-storm of the century wipes out your natural gas and electricity, or an earthquake shakes your house down around your ears in the middle of the night.
Technology, too, is given its due - renewable energy sources like solar and wind are discussed and the best water filters on the market.