The Addiction Research Center Inventory is a 550 item multipurpose test measuring the broad range of physical, emotive, cognitive, and subjective effects of drugs. This manual provides technical information concerning 38 most valid scales, a quantitative method for characterizing the similarity of a profile of scores for the subject, group, or experimental condition with those found for 10 experimental drug conditions and six psychiatric groups, (normal, the mentally ill, alcoholic criminals, opiate addicts, and simulated mental illness determined in opiate addicts), a comprehensive listing of average test scores of all experimental conditions or groups tested, and the degree of similarity of the profile of scores for these conditions or groups with those found for 10 drug conditions and 6 psychiatric categories. The manual also provides some details of the history of the test, scoring, T-score transformation of scores, internal consistency and reliability of scales, and the validity of the scales for a number of purposes. A list of 101 references is included. (Author/SE)