Information on the undereducation of youth living in urban and rural areas within the States is from the published volumes of the 1980 census. The data are analyzed for all racial/ethnic groups separately and are also interpreted for youth with monolingual English-speaking backgrounds and those with non-English language backgrounds. Data are analyzed for youth from families with incomes above and below the poverty level. The study concludes that U.S. education is failing all kinds of youth. It is failing minority and poor youth, who are disproportionately out of school without the minimum education required for entry into employment and responsibility as adult citizens. It is also failing middle-class white majority youth. Of youth who are out of school without high school diplomas -- at least 4.2 million at the latest count -- more than half are native- born, non-Hispanic whites living in homes in which only English is spoken. A large proportion of the undereducated are from families with incomes above the poverty level. Being a member of a minority group or being poor greatly increases the risk that a young person will be undereducated, and minorities are more likely to be poor. The author advises that the extent to which demographic trends will determine the future numbers and composition of the population of undereducated youth through the end of this century depends on the extent to which genuine efforts are made to restructure schools and to help the at-risk groups -- minorities and the poor -- to overtake their more advantaged classmates. 21 figures, 87 tables, chapter notes, a 42-item bibliography, and a subject index