More and more European and North American AIDS researchers are coming to sub-Saharan Africa, which is home to a whopping 70% of all HIV-infected people. These investigators are collaborating with local researchers on projects that aim to slow both HIV's spread and the course of disease in the millions already infected. But most African countries--constrained by limited resources, weak infrastructures, social mores, and political inaction--have grave difficulties translating research insights into prevention and treatment strategies.