Interview with Jean-Paul Moatti, professor of economics and director of the Inserm-IRD research unit “Economic and Social Sciences, Health Systems and Society,” Mediterranean Unit. Prevention must be developed but also reinvented. This is the conclusion reached by Patrick Peretti-Watel and Jean-Paul Moatti in a book published in late 2009. Jean-Paul Moatti emphasizes, in particular, the importance of advancing research and evaluating on-the-ground initiatives. Prevention must take into account the fact that risky behaviors involve both rational and irrational elements. And that, when faced with multiple risks, individuals make trade-offs, taking some risks while avoiding others.