The 1985 Anglo-Irish Agreement (AIA) was one of the major achievements of Anglo-Irish diplomacy during the course of the Troubles. Yet its importance has been misunderstood and often ignored in subsequent histories of the development of the conflict and the peace process. This article seeks to re-evaluate the AIA. It examines the purposes of the agreement, taking issue with a number of the existing explanations. It is argued that London and Dublin had conflicting analyses of what the AIA was designed to do, which led to disappointment in both states with its impact. These differences also made it difficult for academics to accurately characterize the accord. However, the AIA played a profound and imperative role in shaping the subsequent peace process, but this arose out of consequences of the Agreement that were, despite recent claims to the contrary, unanticipated, and indeed unintended, by those who drew up the document. (Palgrave Macmillan)