Abnormal psychology is a subdivision that is limited to the study of the mental processes and behaviour of abnormal people. Properly trained individuals who are more interested in the applied than in the theoretical or academic aspects of psychology are referred to as clinical and consulting psychologists. The causes of abnormal behaviour are complex, and it is not always possible to isolate and evaluate the multiple factors involved. Behaviour should not be mistaken with social behaviour, which is more advanced action, as social behaviour is behaviour specifically directed at other people. The acceptability of behaviour is evaluated relative to social norms and regulated by various means of social control. The behaviour of people is studied by the academic disciplines of psychiatry, psychology, social work, sociology, economics, and anthropology. The present effort to present students of this branch of sociology, that is, human behaviour and abnormal psychology, contains a clear text and methodological analyses of the vital aspects. Contents: Abnormal Psychology; Abnormal Behaviour; Development of Social Feeling; Human Behaviour and Emotions; Development of Mental Process; Humanistic Psychology and Developmental Theory; Mental Disorders and Deficiency; Child Psychology; Mental Health Psychology.