This report describes the results of a major United States Geological Survey (USGS) geologic and oceanographic study of the Gulf of the Farallones, adjacent to the San Francisco Bay region. The first of its kind, the investigation was intended to establish a scientific database for an area of 3,400 square kilometers (1,000 square nautical miles) on the continental shelf for the purpose of evaluating and monitoring human impact on the marine environment. Topics include techniques and technology used in the investigation; oceanography and geology of the Gulf of the Farallones; biology and ecological niches; and issues of environmental management. There is also a list of supplemental reading materials and a glossary. The report is available in two versions: a shorter version for a general audience, and a more technical long version that is also available as a CD-ROM.