A critical review of the progress of science in the United States from 1987 to 1990 will be published as the U.S. National Committee Report to the International Union of Geodesy and Geophysics. As the ninth in a continuing series, the report will be published by the American Geophysical Union on behalf of the USNC. Covering all disciplinary sections of AGU, there port will appear as a supplement to Reviews of Geophysics in 1991 and be distributed at the IUGG General Assembly in August 1991. The final product will not only be a progress report of the prior four years but will also point out the directions for future work in the fields covered. The report will serve to unify those involved in all areas of geophysical research.