The Survey makes accessible the core knowledge of the sciences to curious readers with no special preparation. Within the 377 articles here, 141 cover the major subfields of physical geology, 26 treat areas of economic geology, from essential minerals and other earth resources to the variety of ways man harnesses geothermal, wind, ocean, solar, and nuclear power. Thirty articles examine a range of issues in geochemistry. Geophysics is given full coverage in 35 articles. The planet's history, as well as its impact on the development of life and various early life forms, is explored in 22 articles on fossils, ice ages, dinosaurs, mass extinctions, and evolution. Water is examined in all its forms and sources in 27 articles. There are 36 articles on the solar system, eight on major mountain ranges, soils are done in eight, the atmosphere in 18. Averaging seven pages, articles begin with ready-reference matter and a list of principal terms. A summary section forms the major part of each article, providing a description of either the phenomenon or the methodology. "Context," the concluding section of each essay, presents the conclusions, applications, and implications derived from investigation of the topic. Finally, an annotated, selected bibliography directs the reader to sources that are accessible to the nonspecialist. Cross-references lists articles that offer additional information on the same or a related topic.