John B.F. de Wit, Ph.D. is associate professor of Social Psychology of Health at Utrecht University (The Netherlands), and executive director of the master program in psychology at Utrecht University. His research interests encompass determinants of health behavior and strategies of change, and combine cognitive, motivational and volitional approaches to self-regulation. He has a longstanding involvement in the domains of sexuality and health, emphasizing the promotion as well as the maintenance of protective behaviors in vulnerable populations. Other work is concerned with motivational processes in risk perception and persuasion.