Prof William James is Professor of Virology at the University of Oxford, as well as the Pro-Vice Chancellor for Resources and Planning. His research in virology has concentrated on HIV-AIDS, in particular how the virus replicates and what can be done to prevent this process. In this interview with Professor Denis Noble, he explains how much has been done to develop our understanding of this disease, and how we should be hopeful for the future. They also discuss the origins of the virus and its transmission from chimpanzees in West Africa during the 1970s, and the difficulty of developing effective drugs to combat a virus which can lie latent and replicate rapidly into many different variations. The interview was filmed in the Master's Lodgings, Balliol College, University of Oxford.