Book excerpt: Now in paperback: the runaway British bestseller that has cloudspotters everywhere looking up. Where do clouds come from? Why do they look the way they do? And why have they captured the imagination of timeless artists, Romantic poets, and every kid who's ever held a crayon? Veteran journalist and lifelong sky watcher Gavin Pretor-Pinney reveals everything there is to know about clouds, from history and science to art and pop culture. Cumulus, nimbostratus, and the dramatic and surfable Morning Glory cloud are just a few of the varieties explored in this smart, witty, and eclectic tour through the skies. Illustrated with striking photographs (including a new section in full-color) and line drawings featuring everything from classical paintings to lava lamps, The Cloudspotter's Guide will have enthusiasts, weather watchers, and the just plain curious floating on cloud nine.