Dr. Mathilde Krim at the World AIDS Day Symposium presented by the Foundation For AIDS Research and the Columbia University Mailman School of Public Health in 2002. Krim had a knack for helping people talk about HIV/AIDS rationally, colleagues say. Theo Wargo/WireImage hide caption

Health care workers in South Africa speak to residents during a door-to-door AIDS awareness campaign, part of a series of prevention efforts that has helped lower the country's HIV infection rate. Mujahid Safodien /Reuters /Landov hide caption