Presentations and discussions at the Conference concerned the following topics, among others: (1) the Marijuana Prevention Initiative of the US Department of Health and Human Services; (2) Marijuana Use and the National Drug Control Strategy; (3) Changing Trends, Patterns, and Nature of Marijuana Use; (4) National Marijuana Media Campaign; (5) physical and behavioral effects of marijuana; (6) Consequences of Marijuana Use; (7) Screening for Marijuana Use in Adolescents; (8) Science of Marijuana Testing; (9) Community Prevention Strategies; (10) Antecedents to Marijuana Use and Familial Transmission; (11) Treatment Strategies for Marijuana Use; (12) Relationship Between Marijuana Use and the Use of Other Drugs, and Other Antisocial Problem Behaviors; (13) Innovative Treatment Approaches for Juveniles in the Juvenile Justice System With a History of Marijuana Abuse; and (14) public perceptions of marijuana.