The vibrant red and orange cliffs and spectacular deep canyons of the southwestern United States, the vast salt flats of the Sahara and the rolling sand seas of Arabia, the huge alluvial fans buttressing the high Andes, the steppes of Patagonia, the blood-red Ayers Rock towering over an arid plain in Australia--formed over the course of millions of years, the deserts of the Earth offer landscapes of breathtaking diversity and beauty. Now, in Deserts,...