This introductory chapter frames the issue of religious pluralism as one of enduring significance, with particular relevance to the issue of political stability. How can political societies achieve stability in the face of deep disagreements over issues of profound importance to many people? In recent years, conflicts involving religion have played out in high-profile legal disputes over religious exemptions. This chapter introduces the thesis of the book: that religious pluralism poses a certain challenge to political stability, but it can be resolved via the principles and institutions of political liberalism. This is a way of conceptualizing political liberalism as an instrumental means to the non-moral goal of stability.