The United States Air Force Statistical Digest has been published each year since 1948. Over the years, while the Digest has had several changes in format, the original purpose for publishing it has not changed. The purpose has been, and will continue to be, to compile each fiscal year a single authoritative archival document providing a statistical description of the Air Force in terms of resources, organizations, and major activity parameters. Public affairs officials, scholarly researchers, planners, and many other persons who require a historical description of each year of the Air Force's existence have found the Digest to be an invaluable addition to their information reference sources. This FY1991 Statistical Digest returns to an earlier format containing only actuals and no projections for the future that most always in the past when included in the Digest changed soon after publication. We have also completely reformatted most of the tabular and graphic presentations of data.