Together, the distinction between inclusion / exclusion and the problem of the formation of socio-cultural identities embrace a large variety of social phenomena and theoretical problems that, to a degree independently of one another, have taken shape as central research foci in various theoretical approaches and disciplines in recent years. This special issue of >Soziale Svsteme< addresses different systems theoretical and poststructuralist perspectives dealing with the connection between inclusion and exclusion processes and the constitution of social, cultural and political identities.