Inclusion, the affiliation to and integration of people into communities, must be considered one of the most important fundamental values. It is de facto as significant as that of life itself. An individual cannot develop into a full human and social being if it is not closely included in a social community from birth. After the physical birth, a “social birth” takes place, which lasts until the end of adolescence. In recent sociology, which paid far too little attention to this aspect, there are two approaches. The systems-theoretical perspective sees the differentiation of societal subsystems as an opportunity for all people to freely participate in many different kinds of scoial units. Society-critical approaches argue that today, also as a result of neoliberalism, new forms of social division and exclusion have developed. In this chapter, it is argued that processes of social closure always have two faces: a privileging and a discriminating aspect. Crucial from the perspective of fundamental social values is that the respective social units which use forms of inclusion and exclusion make transparent the principles and methods by which they occur. Three basic types of closure processes are distinguished: (1) in the primarily inclusive processes of enclosure and delimitation, it is about the formation and securing of close social groups and communities (as in personal social relationships in marriage and family, in ethnic and religious communities); (2) in processes of amalgamation and demarcation, it is about the definition of performance criteria by which one can gain access to the respective communities (here, the education system and economic and other organizations are relevant); (3) in the primarily excluding processes of exclusion and marginalization, it is about the custody of or protection from groups of people who are completely included or excluded for various reasons (as in hospitalization, imprisonment, border fortifications through wall construction). For each of these forms, it must be examined whether they are permissible and appropriate from the perspective of fundamental societal values. Positive development trends can also be recognized in this respect, even if new, problematic forms of exclusion continue to emerge.