The European Union referendum of 23 June 2016 proved to be the trigger for the most prolonged period of political turbulence in the peacetime history of the UK; leading to major policy changes and realignments in the party-political system. This book considers from an historical perspective the democratic device that provided the focus for this upheaval. Beginning in the late nineteenth century, it discusses how the idea of using referendums to resolve major political disputes first came onto the agenda, and why. It considers who advocated it, and in what circumstances. The book describes how referendums eventually came into use from the 1970s onwards, and the different patterns in their deployment in the decades that have followed. Major political figures, from Herbert Henry Asquith and Winston Churchill to Clement Attlee, Harold Wilson and Margaret Thatcher; to Tony Blair, David Cameron, and Boris Johnson form part of the story. Governments have come to power and fallen in the context of demands for referendums or the results they produced. The authors provide detailed accounts of each of the 13 major referendums that have taken place. Referendums took place at UK and sub-UK level. They were held on the position of Northern Ireland (1973) and Scotland (2014) within the UK; on devolution to Wales (1979; 1997; 2011) and Scotland (1979; 1979); on the Belfast/Good Friday Agreement (1998); on devolution to London (1998) and North East England (2004); on the parliamentary voting system (2011); and on UK participation in European integration (1975; 1975). The book provides a constitutional and international perspective, and ask how far the original ideas lying behind the referendum were fulfilled in practice.