Synopsis Psychologists all over the world have been trying to make it an objective and scientific discipline. Psychologists have not only traced the history of psychology and understanding of human behaviour, they have conducted experiments on rats and dogs. Psycholgists have tried to have an accurate measurement of human intelligence and perceptions. The concept of intelligence quotient is a major achievement of the modern psychologists. The two world wars have given a boost to the psychological studies on army personnel. The results have been applied to children in schools. Educational psychology has gained much in this direction. Major advances have been made in clinical psychology, where various therapies have been devised. The field of personality development has gained much importance in the domain of psychology. Psychologists like all port have done major work on personality. Perhaps the other major contribution of psychology is in the field of mentally handicapped children. Education of mentally retarded children is a major benefit of psychology which is being made of by governmental and social organizations. This encyclopaedia consists of all major areas of psychology. It is hoped that the encylopaedia will prove to be of immense value to advanced scholars, researchers and university departments of psychology.