In these days of emphasis on environmental problems, studies of clouds and precipitation take on an added importance. Clouds and precipitation cleanse the atmosphere of natural and manmade pollutants or process them for later removal. Cloud radiative and dynamic properties control a good deal more than half of the solar energy available for keeping the atmosphere moving, and precipitation keeps the continents green (or white). Destructive storms are spawned mostly from cloud systems, but Man can modify his local environment to some extent now through the “seeding” of clouds, and possibly he will eventually be able to control severe storms and remove damaging pollutants.