The decennial census was the federal government’s largest and most complex peacetime operation. This report of a panel of the National Research Council’s Committee on National Statistics comprehensively reviews the conduct of the 2000 census and the quality of the resulting data. The panel’s findings cover the planning process for 2000, which was marked by an atmosphere of intense controversy about the proposed role of statistical techniques in the census enumeration and possible adjustment for errors in counting the population. The report addresses the success and problems of major innovations in census operations, the completeness of population coverage in 2000, and the quality of both the basic demographic data collected from all census respondents and the detailed socioeconomic data collected from the census long-form sample (about one-sixth of the population). The panel draws comparisons with the 1990 experience and recommends improvements in the planning process and design for 2010. The 2000 Census: Counting Under Adversity will be an invaluable resource for users of the 2000 data and for policymakers and census planners. It provides a trove of information about the issues that have fueled debate about the census process and about the operations and quality of the nation’s twenty-second decennial enumeration.