The California Student Substance Use Survey marks a milestone in the state's efforts to monitor, understand, and prevent adolescent substance use and abuse. Chapter 1 presents the methodology. This survey follows a shift in California policy to a written parental consent requirement. Sample characteristics, consent procedures, and methods of data analysis are presented and discussed. Alcohol, still the most heavily used drug among teens, is presented and discussed in Chapter 2. Chapter 3 provides data on "Illicit Drug Use." Data on prevalence, heavy use, cessation attempts, first drug use, problems, perceived harm, and perceived availability to teens are discussed in both chapters. Chapter 4, "Level of Involvement," covers the range of use. Chapter 5 provides information on prevention and intervention efforts. Chapter 6 discusses tobacco use and prevention. Chapter 7 provides conclusions and implications for prevention and intervention programs. Despite some fluctuations over the last decade, adolescent use of alcohol, tobacco, and other drugs remains as common among the actively consented sample in the current survey as that of the mid 1980s. An executive summary is included. Appendixes are: (1) "Supplementary Trend Tables"; (2) "The Effect of Active Consent on Response Rates"; (3) "Upper-Grade Survey Instrument." (EMK)