The modern passion for air conditioning began in the 1920s and, as you might guess, it began in Texas, which long ago replaced California as the world capital of unreality. Houston is said to be the most air-conditioned city in the world. In such places ordinary fresh air is regarded with about as much enthusiasm as poison gas. For several months of the year, citizens live in an artificial bubble, very much like space colonists in old science fiction stories – aliens on their own planet. By the 1960s, air conditioning was everywhere, even in places like Maine and Alaska, where the homeowner has to stand alertly poised over the switch, waiting for those few moments of warmth that come and go every summer. The nasty little secret of air conditioning is that it's not even comfortable. The body rebels against those shocking changes from hot to cold and back again, from bright sun and summer smells outside to icy filtered air inside, from short sleeves and sandals to sweaters and wool socks