From 1975 through 1992, data were obtained from 12th grade students and young adult followup. Beginning in 1991, the study was expanded to include 8th and 10th grade students. Students received flyers explaining the study and completed questionnaires during normal class periods when possible. Appreciable declines in drug use were found for high school seniors, college students, and young adults between 19 and 28 years of age over the study period. These declines, however, stalled in 1985 when an increase in active cocaine use was observed. The general decline resumed in 1986 and was joined by a decline in cocaine use in 1987 and a decline in crack use in 1988. Eighth graders exhibited an increase in marijuana, cocaine, LSD, hallucinogen, and inhalant use. By their late 20's, over 75 percent of young adults had tried an illicit drug. About 1.9 percent of high school seniors and 2.3 percent of young adults smoked marijuana daily in 1992. About 28 percent of high school seniors had five or more drinks in a row at least once in the prior 2 weeks, and such behavior tended to increase among young adults 1 to 4 years past high school. Approximately 28 percent of high school seniors were current cigarette smokers, and 17 percent were current daily smokers. The book examines drug effects and attitudes and beliefs about drugs, and appendixes contain prevalence estimates and background and demographic information on the study sample. Footnotes, tables, and figures