The conflict in Northern Ireland was one of the most devastating in postwar Europe. Based on extensive archival research, explores the relationship between the IRA, a highly capable and ruthless clandestine army, and the political movement that developed alongside it to challenge British rule. Finn shows how the radical history of the IRA shaped modern Ireland. In the light of Sinn Féin’s unprecedented electoral success in the Republic of Ireland, and the ongoing Brexit saga with its impact on Northern Irish politics, this book supplies the essential background for an understanding of today’s events.