The IEWG is modeled after the Community Epidemiology Work Group (CEWG) and is an outgrowth of efforts to establish a global drug abuse surveillance network. The reports presented in this volume were based on multiple indicators. Data sources differed by area and network. The analysis of drug abuse in Asia used a standardized instrument in four East Asian and four South Asian cities to collect drug treatment and law enforcement data. The report on Australia used data from meetings of treatment and service agencies in Queensland interviews with users, health workers, researchers, and law enforcement officials; and previous studies. The data for Europe came from household and school surveys and health and police statistics in 15 member countries of the European Monitoring Center for Drugs and Drug Addiction. The paper on Mexico presents treatment, emergency room, drug abuse, police, and medical examiner statistics. Data for South Africa came from multiple sources and were collected in Cape Town, Durban, Port Elizabeth, and Gauteng Province. Information on drug abuse patterns in the United States came from the 1997 National Household Survey on Drug Abuse released in August 1998. The report on Thailand focuses on the use of methamphetamine and other drugs. The final report in the document summarizes initiatives by the World Health Organization to implement scientific studies of global prevention and treatment of drug abuse and strengthening the capabilities of countries to use the knowledge and practices. Tables, figures, and list of IEWG meeting participants