Aided by an extensive range of photographs and illustrations, the author shows how the various properties of sand and its location in the earths crust are diagnostic clues to understanding the dynamics of the earth's surface. The evolution of public health from a field that sought only to limit the spread of acute communicable diseases to one who's goals include health maintenance, wellness, and environmental conditions--and how this evolution fits into the framework of American social, political, and economic developments. Annotation copyrighted by Book News, Inc., Portland, OR