Loneliness affects many, and it harms both individuals and communities. The project “The Social Isolation and Loneliness in Europe Network: Evidence-Based Policy Recommendations on its Causes, Consequences, and Monitoring” (LONELY-EU) is designed to combat this problem: Coordinated by Professor Maike Luhmann, a psychologist at Ruhr University Bochum, Germany, an international consortium is devising methods for sharing knowledge and pooling expertise.