The spread of HIV infection and AIDS depends very much on the way people behave. Individuals from some population groups have been successfully persuaded to modify behaviours that put them at increased risk of HIV infection. How behaviour modification was achieved and how the progress achieved may be maintained are critical questions in controlling the spread of HIV infection. In this context, psychosocial factors have a vital role in influencing behaviour at both the individual and group levels. These factors not only determine who is vulnerable to HIV infection, but also help create opportunities for prevention and determine the obstacles to risk reduction. They may also help to explain what shapes the responses of communities, professionals and policy-makers to the growing epidemic. At the fourth in a series of WHO meetings on AIDS issues, 76 participants met to discuss the psychosocial aspects of HIV infection and AIDS, and to look at the importance of behavioural factors in planning and evaluating strategies for prevention and control. This book looks at these discussions.