João Biehl is the Susan Dod Brown Professor of Anthropology at Princeton University. He is the author of Vita: Life in a Zone of Social Abandonment and Will to Live: AIDS Therapies and the Politics of Survival (Princeton). Adriana Petryna is the Edmund J. and Louise W. Kahn Term Professor in Anthropology at the University of Pennsylvania. She is the author of Life Exposed: Biological Citizens after Chernobyl and When Experiments Travel: Clinical Trials and the Global Search for Human Subjects (both Princeton).