This lesson prompts students to explore the ways that individuals, groups, communities, and nations define who belongs and who does not. The outlined activities examine what it means to belong by introducing the idea of a "universe of obligation," the term sociologist Helen Fein coined to describe the circle of individuals and groups within a society "toward whom obligations are owed, to whom rules apply, and whose injuries call for amends." In this lesson, students will consider their own universes of obligation, as well as those of groups and nations to which they belong. This lesson will prepare students to apply this key concept to a historical case study in their unit or course and to reflect on the way they view others and the society in which they live.