This manual was developed in the belief that youth manifesting significant antisocial behavior should be identified and provided an intervention appropriate to their particular problems. The Assessment Inventory presented has three sections. Section I encompasses issues related to family characteristics, thinking style, behavior, and school/work. Section II focuses on personality and psychological characteristics. It involves a clinical interview, intelligence testing, and psychological testing. Section III provides guidelines for professional judgment/opinion regarding the client. This involves identifying positive factors in the client's behavior and attitudes as well as problems. The administration and scoring of the Assessment Inventory is described, and its use in various settings is discussed. The latter include juvenile probation/court, the mental health system, the welfare system, alcohol and drug treatment, and the school system. 3 tables and a 33-item bibliography