The geothermal program of Fish and Wildlife Service, U.S. Dept. of Interior, aims to develop ecologically sound practices for the exploration, development, and management of geothermal resources and the identification of the biological consequences of such development so as to minimize adverse effects on fish and wildlife resources. This handbook provides information about the ecological effects of geothermal resource development. Chapters are included on US geothermal resources; geothermal land leasing; procedures for assessing the effects on fish and game; environmental impact of exploratory and field development operations; and wildlife habitat improvement methods for geothermal development.