In this important book, one of the most exciting and promising developments in clinical psychology-behavior modification is applied to the treatment of the mentally retarded, particularly those whose behavior poses difficult problems for institutions. Professor Gardner presents an easily intelligible yet detailed account of the concepts and practices of behavior modification and the underlying learning systems, with numerous clinical illustrations of applying specific techniques to various educational and rehabilitation problems. A thorough discussion of the inadequacies of the psychological evaluation systems normally used in education and rehabilitation is offered, along with an alternative behavior analysis approach that provides a method of translating evaluation data into treatment practices. In explaining behavior analysis, the author takes into account the limited behavioral repertoire of the retarded and environmental deficits. Individual chapters on respondent, operant, and observational learning, and a detailed discussion of a functional analysis approach to evaluation, are included. Proven behavior modification strategies are presented along with a review of related research and clinical studies. The book closes with a detailed description of a research program for the design and testing of sheltered workshop systems for the retarded and emotionally disturbed. The positive approach inherent in the belief that behavior is modifiable-even in the severely limited retarded-is in marked contrast to the pessimism of other systems of therapy, education, and training. Also, the author has concentrated throughout on making the book understandable to clinicians and students with no previous knowledge of behavior modification. Besides serving as a valuable handbook for all treatment personnel, the book can also be used as a basic text for various courses dealing with mental retardation.