Progress has been made over recent decades in the development of effective programmes to reduce the risk of mental disorders, and evidence exists that mental health can be enhanced by effective public health and social interventions. Research evidence also illustrates the close interaction between mental health, physical health and behaviour. The published evidence on prevention and promotion comes mainly from high-income countries, and culture specific factors have been inadequately studied. However the extent of available evidence and the principles derived from it are sufficient to plan and evaluate new programs in high-, middle- and low-income settings. A challenge now is to evaluate and refine programmes and good practice in settings and vulnerable groups other than those already included. Progress in promotion and prevention also requires monitoring of the mental health effects of interventions in fields other than mental health, and conversely the effect of interventions designed to improve mental health on the broader health and productivity of individuals and communities. This plenary and the related symposia aim to extend understanding of the evidence on the effectiveness of promotion and prevention, and the principles on which these are based, especially those derived from programmes and policies that are developed or adapted locally in countries and settings of various types and cultures.