Calculating dropout rates is difficult because of definitional and data problems. However, nationally, slightly less than three-quarters of all 18-year-olds and 19-year-olds have completed high school. Poor academic performance is the best predictor of who drops out of school. Students who are rebellious, delinquent, chronically truant, or pregnant are also more likely to drop out. Dropouts have more difficulty than others in finding and holding jobs. Their annual and lifetime incomes are substantially less than those who complete high school. An estimated 40 percent of dropouts subsequently return to the educational system, and about 30 percent eventually receive a high school diploma or alternative credential. Those who are more likely to return are whites, those with higher test scores, and those from families of higher socioeconomic status. Findings indicate that a crucial factor in preventing dropouts may be the early identification of potential dropouts so that services can be provided prior to high school. In addition, greater efforts to bring dropouts back into the educational system and more flexible high school programs for youthful workers or parents are needed. Figures, tables, and 24 messages.