Book reviewed in this articles:Mental Retardation and Behavioural Research. Study Group No. 4. Ed. by A. D. B. CLARKE and A. M. CLARKE.The Study of Games. E. M. Avendonand B. Sutton‐Smith.The Effects of Psychotherapy. S. Rachman.Neonatal Behavioural Assessment Scale. T. BerryBrazelton.Language, Brain, and Hearing. J. G. Wolff.Follow up Study of Hospitalized Adolescents. B. Garber.Current Issues in Adolescent Psychiatry. Edited by J. C. Schoolar.Current Issues in Adolescent Psychiatry. Edited by J. C. Schoolar.Theories of Cognitive Development: Implications for the Mentally Retarded. Ed. by R. M. Allen, A. D. Cortazzoand R. P. Toiste