The present book is the outcome of the Ph.D. work undertaken in the Department of Psychology, University of Delhi on the topic ‘Cognitive Behavioural Intervention in controlling Conduct Disorder-A community based study’. About 3 years of dedicated work as a Researcher, with children from diverse backgrounds, under the aegis of Delhi Social Welfare Board and some NGOs has contributed to the making of the present book. Conduct disorder is one of the most common externalizing behavioural disorders of childhood representing a broad group of behaviour, ranging from aggressive, and non-complaint behaviour to delinquency. It includes behaviours, which are in conflict with the environment. As contrast to radical behaviourism, emphasis is placed on cognitive strategies by teaching what to think and how to think. This exercise helps better generalization of skills beyond the therapeutic setting.