Didier Fassin is the James D. Wolfensohn Professor of Social Science at the Institute for Advanced Study in New Jersey and the Annual Chair of Public Health at the Collège de France. He is the author of many books in the fields of medical and political anthropology, including Life: A Critical User’s Manual and Writing the World of Policing: The Difference Ethnography Makes. Marion Fourcade is professor of sociology at the University of California, Berkeley. She is the author of Economists and Societies: Discipline and Profession in the United States, Britain, and France, 1890s to 1990s and has published widely in the fields of economic sociology, culture, and science and technology.