One of the primary goals of the World Health Organization (WHO) Department of Mental Health and Substance Abuse is to reduce the burden associated with mental, neurological and substance abuse disorders. Prevention of these disorders is obviously one of the most effective ways to reduce the burden. A number of World Health Assembly and Regional Committee Resolutions have further emphasised the need for prevention. WHO published a document on primary prevention of mental, neurological and psychosocial disorders in 1998 (WHO, 1998). However, this scientific field has seen rapid development of ideas and research evidence, necessitating a fresh review. This Summary Report (along with the forthcoming Full Report) attempts to provide a comprehensive overview of this field, especially from the perspective of evidence for effective interventions and associated policy options. This is in accordance with the WHO mandate to provide information and evidence to Member States in order to assist them in choosing and implementing suitable policies and programmes to improve population health. In an area like prevention of mental disorders this task is even more critical since much evidence is recent and untested in varied settings.