This chapter introduces the book as the first of a two-volume study which seeks to provide a comprehensive analysis of devolution in the UK. It focuses on the period from 1997 to 2007, addressing the origins and introduction of the original devolution settlements, and the subsequent decade of their development until the end of the Blair government in 2007. In these years, the original devolution reforms followed extensive debate in the 1980s and 1990s, including in Northern Ireland a peace process and talks that led ultimately to the historic 1998 Belfast Agreement. Referenda in each of Scotland, Wales and Northern Ireland were held in 1997. The subsequent development of devolution up to 2007 included the move to start at least a debate about further reform in Scotland, as well as more immediately a second Government of Wales Act in 2006. In Northern Ireland, the 2006 St Andrews Agreement reset the terms of the original 1998 settlement, and enabled the resumption of devolution in 2007, after the Northern Ireland Assembly had spent more time suspended than in session. A referendum on an elected assembly for the North East in 2004 ended in a 'no' vote, but the powers of central government offices in the English regions, Regional Development Agencies and indirectly elected regional assemblies nevertheless increased.