This chapter examines multiculturalism and its main assumptions, especially the emphasis on the need to supplement the focus on common rights with greater attention to cultural diversity and group-differentiated rights. It begins with a discussion of three distinct stages in the debate over multiculturalism. In the first stage, proponents of multiculturalism were initially drawn to communitarianism as a possible philosophical foundation for minority rights. The second stage of the debate revolves around the question of the possible scope for multiculturalism within liberal theory, and the third stage highlights the role of multiculturalism in nation-building. The chapter proceeds by describing five types of ethnocultural groups that are found within Western democracies and how they have been affected by majority nation-building: national minorities, immigrants, isolationist ethnoreligious groups, metics, and racial caste groups such as African Americans. It concludes with an analysis of the politics of multiculturalism.