ISSUES ADDRESSED ARE THE METHODOLOGY OF RESEARCH ON DRUG ABUSE; THE EPIDEMIOLOGICAL, SOCIAL, PSYCHOLOGICAL, PHARMACOLOGICAL, AND LEGAL ASPECTS OF THE YOUTH DRUG-ABUSE PROBLEM; AND THE IMPLICATIONS FOR PLANNING DRUG-ABUSE TREATMENT AND PREVENTION PROGRAMS AND DETERMINING POLICY. THE PRINCIPAL FOCUS IS ON EPIDEMIOLOGY AND DRUG ABUSE PATTERNS. SUPPORTING DATA SOURCES INCLUDE FOUR NATIONAL DRUG ABUSE DATA BASES--THE NATIONAL YOUTH POLYDRUG STUDY, THE CLIENT-ORIENTED DATA ACQUISITION PROCESS, THE DRUG ABUSE REPORTING PROGRAM, AND THE DRUG ABUSE WARNING NETWORK. PRESENTATIONS ENCOMPASS THE VARIOUS METHODS AND APPROACHES OF A GROUP OF EXPERTS, EXPERIENCED RESEARCHERS, AND AUTHORS TO THE ANALYSIS OF THE DATA BASES AND THEIR VARIOUS PERSPECTIVES ON THE FINDINGS FROM THESE ANALYSES. ONE MAJOR PORTION OF THE VOLUME CONSISTS OF A SYSTEMATIC REVIEW OF METHODOLOGICAL ISSUES IN DRUG-ABUSE RESEARCH, FOLLOWED BY A CONSIDERATION OF THE METHODOLOGICAL ISSUES AND PROCEDURES THAT WERE INVOLVED IN THE NATIONAL YOUTH POLYDRUG STUDY. SPECIFIC ISSUES AND ASPECTS OF YOUTH DRUG ABUSE ARE EXAMINED IN A SECOND MAJOR GROUPING OF STUDIES, INCLUDING DRUG USE PATTERNS, FEMALE ADOLESCENT DRUG USE, THE RELATIONSHIP BETWEEN DRUG USE AND DELINQUENT AND CRIMINAL BEHAVIOR, THE INTERACTION OF DRUG USE AND EDUCATIONAL EXPERIENCES, DRUG PHARMACOLOGY, AND ISSUES RELATED TO JUVENILE USE OF MARIHUANA AND ALCOHOL. ANOTHER MAJOR CATEGORY OF PRESENTATIONS CONSIDERS TYPES OF DRUGS USED BY YOUTH AND THE HAZARDS ACCOMPANYING THEM. DRUG USE IN SPECIFIC MINORITY, ETHNIC YOUTH GROUPS AND IN A RURAL YOUTH POPULATION IS ALSO EXPLORED. THE FINAL SECTION INCLUDES DESCRIPTIONS OF THE TREATMENT RESOURCES, FACILITIES, AND SERVICES AVAILABLE FOR DRUG-ABUSING YOUTHS; AN ASSESSMENT OF WHAT HAS BEEN LEARNED ABOUT THE TYPES OF TREATMENT THAT ARE SUCCESSFUL WITH YOUTH; A REPORT ON THE EVALUATION OF THE OUTCOME AND EFFECTS OF VARIOUS TREATMENT PROGRAMS; AND THE DEMOGRAPHIC, DRUG-USE, AND PSYCHOSOCIAL FACTORS THAT PREDICT SUCCESSFUL TREATMENT OUTCOME. SUPPORTING TABULAR DATA ACCOMPANY EACH PRESENTATION, ALONG WITH REFERENCES. (RCB)