The book addresses the impact of the European Union (EU) on subnational mobilization in small unitary states. Located at the intersection of contributions from the literatures on multilevel governance and Europeanization, this book offers a new theoretical framework to account for state rescaling processes in small unitary states. By means of a comparative analysis of eight small unitary states in Europe, this book shows that the impact of the EU on subnational mobilization is filtered through domestic mediating factors which can lead to three possible outcomes: decentralization, recentralization or no change. The book offers a balanced combination of analytical clarity and the richness of empirical accounts in a wide diversity of case studies. It sheds a new light on the ‘hybrid nature’ of the European polity and demonstrates that member state governments have remained the most important pieces of the European puzzle. Overall, it arrives at two conclusions: first, that we are witnessing a ‘transformation of the state’ rather than its demise; second, the notion of a ‘Europe of the Regions’ in small unitary states was no more than a ‘damp squib’. The chapters in this book were originally published as a special issue of the journal, Regional & Federal Studies.