Researchers have developed a sophisticated new probe that detects HIV’s hiding places inside and outside of cells. “It’s a fantastic new technique that’s going to allow us to visualize the virus in tissues like we’ve never been able to before,” says immunologist Richard Koup, deputy director of the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases (NIAID) in Bethesda, Maryland, who was not involved in the research. Insights from this high-powered molecular microscope, revealed at an international AIDS conference last week, may clarify critical questions about HIV persistence and, ultimately, about how to rid the body of the virus.