This book decisively advances the academic debate on politicisation beyond the state of the art. It is the first book to theorise and conceptualise ‘politicisation’ across the epistemic communities of different subdisciplines, bringing together the different strands in the debate: (international) political theory, political sociology, comparative politics, EU studies, legal theory and international relations. This provides a comprehensive discussion of different concepts of politicisation, their ontological and theoretical backgrounds, and their analytical value, including speech-act, practice- and actor-oriented approaches. Furthermore, the linkages of politicisation to the concepts of politics and the political, democracy, depoliticisation, juridification, populism, and Euroscepticism are clarified. Finally, the book shows how the methodological toolbox in empirical politicisation research can be completed regarding different arenas, actors and modes of politicisation. The volume thus provides a much-needed theoretical and conceptual reflection to the newly emerging research field of politicisation in order to recognise and define the key issues and build a solid foundation for further debate and empirical research.