This chapter establishes the main issues to be explored in this book, including the dramatic transformation that Sinn Féin and the IRA underwent. It provides a critique of existing explanations, arguing that they mistakenly assume the politics of Sinn Féin is driven primarily by the military capacity of the IRA. Existing explanations also assume that interplay between the British state and Irish republicans led to their moderation, but these explanations neglect the wider institutional context in which republicans chose to change their strategy. In contrast, this chapter sets out the argument that sustained contact with, and inclusion in, key political processes, namely party politics and a consolidated framework of democratic institutions, extracted moderate concessions from republicans in a gradual and path-dependent process.