Our preliminary agenda for the Pathogenesis meeting is organized in 10 plenary sessions, each showcasing the latest insights gained from studying a particular aspect or model of HIV and HIV-related illness. Individual sessions will, for example, highlight recent studies of the HIV virion, its growth in infected cells and tissues, its resistance to antiviral drugs, and its transmission in human populations. Others will feature illuminating work on related viruses and viral diseases, including simian AIDS. Two sessions on HIV immune responses will be convened jointly with the Vaccines symposium, as will the keynote address. We also envision at least two afternoon workshops featuring speakers chosen from submitted abstracts, as these offer an opportunity to involve new and lesser-known investigators. The HIV/AIDS pandemic remains one of the greatest virological threats to human health both in the United States and worldwide. The Keystone Symposium on HIV Pathogenesis ranks as the premier venue for the latest research aimed at understanding HIV disease and developing effective therapies to control or prevent it.