Young children who display temper tantrums, poor self-control, noncompliance with parent and teacher requests, and unskilled or aggressive behaviors with peers cause problems for themselves and those around them at home, at school, and in the neighborhood. During adolescence, such conduct problem behaviors have more serious consequences than during early childhood and often bring the youth to the attention of authorities in the school and juvenile justice systems. Conduct problems are the most common reason for referrals to child mental health clinics in the western hemisphere (Frick, 1998) and have the poorest prognosis for adult adjustment of any childhood disorder (Kohlberg, Ricks & Snarey, 1984). Conduct problems are associated not only with pervasive developmental failures (Capaldi & Stoolmiller, 1999) in various key domains, such as academics, but also with serious and maladaptive behaviors during adulthood, such as substance abuse (Wiesner, Kim & Capaldi, in press) and violence toward romantic partners (Capaldi & Clark, 1998). Conduct problems thus have been the target of nationwide efforts in a variety of countries to understand causes and consequences, to prevent emergence, and to treat symptoms.