This survey, monitoring levels of substance abuse in the United States, serves as a tool for researchers and policymakers to better understand and control substance abuse problems. It provides information on 25,500 participants' use of illicit drugs, alcohol, and tobacco among the civilian, noninstutionalized population. Trends for the years, 1979, 1985, and 1991 through 1998 are included. For each drug (marijuana, cocaine, inhalants, hallucinogens, heroin, non-medical use of psychotherapeutics, alcohol, cigarettes, and smokeless tobacco), there are tables arranged to facilitate group comparisons. Data for the total population is presented for each of four age groups, and then compared by sex, race/ethnicity, population density, region, adult education, and current employment. Data on drug use among special populations (drug use and criminal behaviors, drug use and pregnancy, drug use among adolescents exposed to drug education messages) is also included. Seven appendixes detail procedures: Appendix A contains definitions of key terms; Appendixes B, C, and D include information on the quality of data and testing procedures; Appendix E explains the adjustment procedure that was applied to the 1979-1993 NHSDA estimated in order to facilitate long-term trend analysis; Appendix F contains answer sheets for 1998 NHSDA questionnaire; Appendix G contains pages from the questionnaire. (Contains 124 references.) (Author/JDM)