Much of his work since 1987, first at the World Bank and now at the CGD, is on the economics of the AIDS epidemic. After work on the economic impact of the AIDS epidemic and on cost-effective interventions, he co-authored the Bank’s first comprehensive treatment of the economics of AIDS in the book, Confronting AIDS: Public Priorities for a Global Epidemic (1997,1999). His most recent book is Achieving an AIDS Transition: Preventing Infections to Sustain Treatment (2011)in which he offers options, for donors, recipients, activists and other participants in the fight against HIV, to reverse the trend in the epidemic through better prevention. His previous publications include The Economics of Effective AIDS Treatment: Evaluating Policy Options for Thailand (2006). Other papers examine the economics of preventing and of treating malaria.