Tho present thesis represents a summary or research done by the author (and others) that was conducted with heroin addicts and drug abusers undergoing behavioral and pharmacological therapy at Stockton State Hospital, Stockton, California. From June 1970 to December 1970 the Research Department of Stockton State Hospital, in conjunction with the Drug Abuse Program at Stockton State Hospital, conducted research investigating a number of difference facets relating to inpatient programs for heroin addicts undergoing methadone maintenance and drug abusers. These facets included the investigation and evaluation of (a) motivational factors; affecting the voluntary participation of inpatient heroin addicts and drug abusers in behavioral and pharmacological therapy, (b) the effectiveness of the synthetic narcotic methadone hydrocloride as a primary reinforcing technique for appropriate behavior, (c) the effectiveness of various therapeutic approaches used in conjunction with behavioral modification techniques, and (d) the effect of methadone on perceptual and motor functioning in the heroin addict under-going methadone maintenance. The present thesis is a compilation cf these research projects.