This book uses the case of Northern Ireland to evaluate theoretical approaches in international relations. It investigates the process of negotiation that led to the signing of the Good Friday or Belfast Agreement and the continuing challenges to peace reconciliation in Northern Ireland. Incorporating the work of leading scholars, it explores a wide range of topics, including the function of deception in promoting peace, the question of partition and how it was reimagined by nationalists such as John Hume, and how the decommissioning process led to a role in internal policing for paramilitaries. The influence of outside actors - notably the United States and the European Union - is also considered, along with the involvement of the Catholic Church and the marginalization of women. This book will be important for academics interested in theories of international relations and to a wider public interested in understanding the Northern Ireland peace process.