Widespread concerns exist in the public debate that solidarity erodes in Western societies. Empirical evidence relating to these concerns, however, is weak. In order to assess these issues, to clarify the leading concepts for analyzing the strength and the development of the “social bond” and to shed light on the main sources that condition its strength, an international conference is organised. The aims of the conference are threefold: first, to describe different forms of solidarity and to analyze their change, second to check whether the fear, that the social bond is weakening, is justified, and third to clarify the social preconditions of solidarity.