The National Environmental Policy Act of 1969 requires an environmental impact statement for any major federal action affecting the human environment. Now many state and local governments require impact statements from state agencies or private agencies. This handbook presents a standardized approach to the development and implementation of policy. Reviewed are requirements and proposals by states and other political subdivisions. Discussed is the content, format, and interpretation of impact statements. Recommended guidelines for preparing impact statements are outlined. Included are descriptions of projects and the existing environment, impacts of/on the environment, alternative strategies, unavoidable adverse impacts, impacts over time, and irreversible/irretrievable commitments. The appendices contain addresses for available guidelines, annotated and selected bibliographies, manuals, and newsletters, a listing of public and private organizations, and a review of interpretation of impact statements in the courts. (MR)