WEATHER

Remarking that ``nothing about the weather is very simple,'' Simon goes on to describe how the sun, atmosphere, earth's rotation, ground cover, altitude, pollution, and other factors influence it; briefly, he also tells how weather balloons gather information. Even for this outstanding author, it's a tough, complex topic, and he's not entirely successful in simplifying it; moreover, the import of the striking uncaptioned color photos here isn't always clear. One passage—``Cumulus clouds sometimes build up into towering masses called cumulus congestus, or swelling cumulus, which may turn into cumulonimbus clouds''—is superimposed on a blue-gray, cloud-covered landscape. But which kind of clouds are these? Another photo, in blue-black and white, shows what might be precipitation in the upper atmosphere, or rain falling on a darkened landscape, or...? Generally competent and certainly attractive, but not Simon's best. (Nonfiction. 10-12)