In my younger days, I was an avid touring cyclist. With my teaching duties complete for the year, I would load up my bicycle and pedal across the country in June and July, searching for adventure wherever I could find it. One particular tour I took involved one of the hottest days of cycling I ever endured: a hundred miles ridden at temperatures that topped out around 108 degrees during the dead of the afternoon. By the time I reached my destination that day, a tiny desert town with only one motel available, all I could think about was a gallon of iced water and a cool place to drink it. I’ll never forget the feeling of the air conditioning when I stepped through the motel room door that day, the stark transition between the furnace outside and the cooling relief of the dark room inside. I remember turning the air conditioner, a window unit, up as high as it would go, the frigid air blowing through my hair and cooling my skin, and the relief intensified. I thought about how miserable the conclusion to that day would have been had a good air conditioner not been available, how necessary it was to the good night’s sleep I was going to need to get back out on the road the next day. Then I thought of what desert life must have been like before air conditioning was available, before it was possible to simply press a button or turn down a thermostat and enjoy instant cooling.