During 25 years of research since HIV-1 was first identified in Paris, there have been great advances in our understanding of the virus and of the immune system. Practical advances include the early development of diagnostic tests of infection that made blood donation safe, and since 1996, combination anti-retroviral therapy that has great reduced incidence of AIDS in HIV-infected people who have access to the drugs. HIV prevention through behavioural change has been successful, and we do not yet have any safe and efficacious microbicides or vaccines.