This report builds upon a series of National Center for Education Statistics (NCES) reports on high school dropout and completion rates that began in 1988. It presents estimates of rates in 2008, provides data about trends in dropout and completion rates over the last three and a half decades (1972-2008), and examines the characteristics of high school dropouts and high school completers in 2008. Four rates are presented to provide a broad picture of high school dropouts and completers in the United States, with the event dropout rate, the status dropout rate, the status completion rate, and the averaged freshman graduation rate each contributing unique information. Data presented in this report are drawn from the annual October Current Population Survey (CPS), the annual Common Core of Data (CCD) collections, and the annual General Education Development Testing Service (GEDTS) statistical reports. Appendices include: (1) Technical Notes; (2) Glossary; and (3) Standard Error Tables. (Contains 28 tables, 6 figures, and 28 footnotes.)