Foreword Peter Piot; Introduction Bjørn Lomborg; Part I. The Research: Section 1. Sexual Transmission of HIV Jere R. Behrman and Hans-Peter Kohler: 1. Alternative perspective: sexual transmission of HIV Damien de Walque; 2. Alternative perspective: sexual transmission of HIV Alan Whiteside; Section 2. Prevention of Non-sexual Transmission of HIV Lori A. Bollinger: 3. Alternative perspective: prevention of non-sexual transmission of HIV Rob Baltussen and Jan Hontelez; 4. Alternative perspective: prevention of non-sexual transmission of HIV Mira Johri; Section 3. Treatment Mead Over and Geoffrey P. Garnett: 5. Alternative perspective: treatment Robert J. Brent; 6. Alternative perspective: treatment John Stover; Section 4. Strengthening Health Systems William P. McGreevey, with Carlos Avila and Mary Punchak: 7. Alternative perspective: strengthening health systems Till Bärnighausen, David E. Bloom and Salal Humair; 8. Alternative perspective: strengthening health systems Nicoli Nattrass; Section 5. Social Policy Interventions to Enhance the HIV/AIDS Response in Sub-Saharan Africa Anna Vassall, Michelle Remme and Charlotte Watts: 9. Alternative perspective: social policy interventions to enhance the HIV/AIDS response in sub-Saharan Africa Tony Barnett; 10. Alternative perspective: social policy interventions to enhance the HIV/AIDS response in sub-Saharan Africa Harounan Kazianga; Section 6. Vaccine Research and Development Robert Hecht and Dean T. Jamison, with Jared Augenstein, Gabrielle Partridge and Kira Thorien: 11. Alternative perspective: vaccine research and development Steven Forsythe; 12. Alternative perspective: vaccine research and development Joshua A. Salomon; Part II. Ranking the Opportunities: Section 7. Findings of the Nobel Laureate Economist Expert Panel Ernest Aryeetey, Paul Collier, Edward C. Prescott, Thomas C. Schelling and Vernon L. Smith: 13. Findings from African civil society Bactrin Killingo, Nduku Kilonzo, Christiana Laniyan, Retta Menberu and Ken Odumbe; 14. Conclusion Bjørn Lomborg.