This book seeks to explain centralisation and decentralisation, which are conceptualised as having three dimensions: an institutional (polity), a functional (policy), and an actor- and process-oriented dimension (politics). In terms of theory, three separate approaches are combined: socio-cultural, political-ideological, and macro-structural. Empirically, the book compares decentralisation within the Swiss cantons as 26 independent units of observation. Cantonal decentralisation is first predicted cross-sectionally using linear regression models. Three significant independent variables emerge: political culture, area, and the strength of left-wing parties. Then, using process tracing, four cantons are studied over time to move from identifying correlation to establishing causation. Finally, causal inferences for (de)centralisation as such are drawn, urging future federal and territorial politics studies to a) reconceptualise decentralisation into three distinct but related dimensions and to b) bridge the theoretical gap between socio-cultural, structural and party-political approaches to achieve more valid and reliable explanations of territorial governance. 'The subtitle of Why Centralisation? is an apt choice: indeed, concept, theory, and evidence do come together in this remarkable piece of scholarship. The foundations of the book rest on a within-case comparison, but Why Centralisation? is driven by something more than concerns of social science methodology; there are important substantive and theoretical lessons here. National indicators often miss out on regional variation, but there is a lot to be learned from seeking to explain why sub-units behave differently... The book brings together ideas from different schools of analysis, and puts this through the filter of various research methodologies. Quantitative indicators and archival evidence together provide the empirical grounding to Mueller's quest to explain the variation. The result is scholarship in the grand book tradition where big questions are coupled with in-depth case-studies. Not only does one get a theoretically-driven, novel way of conceptualising what (de)centralisation means, one also gets a very interesting glimpse into the politics and history of the Swiss cantons.' Jan Erk, Reader in Comparative Politics, University of Leiden 'A groundbreaking demonstration of how readily available, reliable data can be used to enrich understandings of the subnational dynamics of governance. Mueller shows that to fully understand the differing degrees, options and supports for decentralisation within federal and decentralised countries - or the different triggers and responses to centralisation imperatives - a stronger focus needs to be given to the combined influences of local and regional culture, policy needs and politics. However, in his new tracking of the relationship between these influences and (de)centralisation outcomes, he not only draws on rich qualitative evidence from Switzerland but lays the ground for more effective and efficient comparative research into these drivers and outcomes across many countries.' A J Brown, Professor of Public Policy and Law, Griffith University