The Anglo-Irish Treaty was signed on 6 December 1921. The Treaty led to the creation of an independent Irish state, but also a devastating Civil War that defined Irish politics for decades. Divisive as it proved to be, the signing of the Treaty one of the most important milestones in modern Irish history. The original Irish copy of the Treaty is perhaps the most famous document in modern Irish history and is retained in the collections of the National Archives in Dublin, which marked the centenary of its signing with the landmark exhibition The Treaty, 1921: Records from the Archives. This lavishly illustrated book, based on the original exhibition, explores the negotiation and signing of the Treaty by the Irish delegation that travelled to London in October 1921, and their day-to-day experience of life in London as the negotiations moved towards their conclusion. It does so through the documentary record that they left behind, much of it retained by the National Archives in Dublin and other archives in Ireland.