How can we facilitate the transfer and application of scientific knowledge in everyday practice? This issue examines the value of relying on evidence—by integrating both scientific knowledge and the experiential knowledge of professionals and users—in the fields of prevention and health promotion. The current COVID-19 pandemic has highlighted our difficulties in thinking and acting during times of health crisis and uncertainty. Some thirty experts—ranging from researchers to frontline professionals—have contributed to this special issue coordinated by Béatrice Lamboy, Marie-Odile Frattini, Marie-Renée Guével, Zeina Mansour, Benjamin Soudier, Mélanie Villeval, and Pierre Arwidson.