'HIV and AIDS in South Asia: An Economic Development Risk' offers an original perspective on HIV and AIDS as major development issues for the region. Although the impact of HIV and AIDS on economic growth appears to be very small, three risks to development are associated with HIV and AIDS in South Asia: the risk of escalating concentrated epidemics, the economic welfare costs, and the fiscal costs of scaling up treatment. As the authors show, South Asian countries have relatively low estimated national HIV prevalence rates, but prevalence is growing rapidly among vulnerable groups at high risk, such as sex workers and their clients, men having sex with men, and injecting drug users and their partners. The cost benefits of targeted prevention programs are high, and the financing of prevention measures such as comprehensive harm reduction and condom use is a sound economic investment in low-prevalence countries with concentrated epidemics. Interventions that reduce the risks and stigma associated with HIV and AIDS have benefits beyond the cost of lives saved; they improve the welfare of those who are at risk and those who fear contracting HIV. Treatment for AIDS in South Asia is limited at present, with weak health systems contributing to low access to and use of services. The challenges of a comprehensive scaling up of antiretroviral treatment are substantial, underscoring the crucial role of effective prevention today. The authors conclude that the limited ability of many households to pay 'catastrophic' health expenses associated with treatment, as well as the negative consequences associated with poor adherence to treatment, suggest a large and central role for the public sector in the provision of antiretroviral therapy. 'HIV and AIDS in South Asia: An Economic Development Risk' will be of particular value to readers with interests in the areas of economic policy, microfinance, public health, and epidemiology.