Modernity understood ‘engagement’ in individual or collective terms. Weber and Marx offered the best-known and exemplary paradigms. Since then, a great deal of sociologists have tried to combine them and have seen engagement as a co-determination between agency and social structure. Everybody knows that engagement entails acting in and with social relations, but the intrinsically relational character of engagement has remained obscure, largely implicit and unexplored. Engagement has always been a social relation, but nowadays it is taken on an unprecedented morphogenetic connotation. The proposals for devising a new ‘relational sociology’ of engagement are on the increase. Yet these proposals are very different in their theoretical, methodo...