It is now forty years since the discovery of AIDS, but its origins continue to puzzle doctors, scientists and patients. Inspired by his own experiences working as a physician in a bush hospital in Zaire, Jacques Pépin looks back to the early twentieth-century events in central Africa that triggered the emergence of HIV/AIDS and traces its subsequent development into the most dramatic and destructive epidemic of modern times. He shows how the disease was first transmitted from chimpanzees to man and then how military campaigns, urbanisation, prostitution and large-scale colonial medical interventions intended to eradicate tropical diseases combined to disastrous effect to fuel the spread of the virus from its origins in Léopoldville to the rest of Africa, the Caribbean and ultimately worldwide. This is an essential perspective on HIV/AIDS and on the lessons that must be learned as the world faces another pandemic.