Across Western Europe, the global financial crisis of 2008 and its aftermath not only brought economic havoc but also, in turn, intense political upheaval. Many of the political manifestations of the crisis seen in other Western and especially Southern European countries also hit Spain, where challenger parties caused unprecedented parliamentary fragmentation, resulting in four general elections in under four years from 2015 onwards. Yet Spain, a decentralised state where extensive powers are devolved to 17 regions known as ‘autonomous communities’, also stood out from its neighbours due to the importance of the territorial dimension of politics in shaping the political expression of the crisis. This book explains how and why the territorial dimension of politics contributed to shaping party system continuity and change in Spain in the aftermath of the financial crisis, with a particular focus on party behaviour. The territorial dimension encompasses the demands for ever greater autonomy or even sovereignty coming from certain parties within the historic regions of the Basque Country, Catalonia and, to a lesser extent, Galicia. It also encompasses where these historic regions sit within the broader dynamics of intergovernmental relations across Spain’s 17 autonomous communities in total, and how these dynamics contribute to shaping party strategies and behaviour in Spain. Such features became particularly salient in the aftermath of the financial crisis since this coincided with, and indeed accelerated, the rise of the independence movement in Catalonia.