This monograph reports findings through 1993 from the ongoing research and reporting series entitled Monitoring the Future: A Continuing Study of the Lifestyles and Values of Youth. The study has consisted of in-school surveys of nationally representative samples of high school seniors each year since 1975 and of eighth and tenth grade students each year since 1991. The findings show that the classes of illicitly used drugs that have had an impact on appreciable proportions of young Americans in their late teens and early twenties are marijuana, cocaine, stimulants, LSD, and inhalants. In 1993, high school seniors use of these drugs showed annual prevalence rates of 26 percent, 3 percent, 8 percent, 7 percent, and 7 percent respectively. Despite the fact that it is illegal for virtually all high school students and most college students to purchase alcoholic beverages, experience with alcohol use is almost universal among them (67 percent of eighth graders have tried it, 81 percent of tenth graders, and 87 percent of 12th graders). Survey findings also show that by late adolescence sizeable proportions of youths still are establishing regular cigarette habits, in spite of the demonstrated health risks associated with smoking. Since the study began in 1975, cigarettes have consistently comprised the class of substance most often used on a daily basis by high school students. Extensive tabular and graphic data