Session 1: Governance in the European UnionThis book argues that a third wave of research on the EU is needed to adequately understand the increased interconnectedness between the European and national political levels. We posit that this third wave should be sensitive to the temporal dimension of European integration and Europeanization. In particular, we seek to link the processes of Europeanization and European integration in a new way by asking the question: how has Europeanization affected current modes of integration and cooperation in the EU? Preparing the ground for the third wave, the first part of the book concerns Europeanization. In order to fully understand the feedback of Europeanization on cooperation and integration it is important to analyze how European integration has had an impact on member states in the first place, in particular indirectly, beyond the direct mechanism of compliance with European policies. The research presented here stresses the role which domestic actors and in particular governments have in guiding the Europeanization impact on the member states. The second part of the book concerns integration and cooperation, in line with what we see as a third wave of research. Here we analyze how prior integration effects, that is Europeanization, influences current preferences for integration. We find that earlier integration effects have had a significant influence on those preferences, resulting however, somewhat surprisingly not always for a preference for closer integration. The multi-faceted interrelationships between the EU level and the national level and the increased interconnectedness between them cast doubt on the appropriateness of traditional readings of central concepts of political science and international relations such as territory, identity and sovereignty. The final section of the book therefore concerns the conceptual challenges faced by the continued development of multi-level governance. These contributions show that a conceptual reorientation is necessary because up until now these concepts have been almost exclusively linked to the nation state. One of the key findings of the book is the astonishing variation in modes of cooperation and integration in the EU. We suggest that this variation can be explained by taking into account the sources of legitimacy at the national and at the EU level on which cooperation and integration are based. We argue that whereas economic integration, in particular the creation of a single market, could be sufficiently backed by output legitimacy, deeper integration in other areas requires a degree of input legitimacy that is currently lacking in the EU. Therefore, non-economic integration is often taking the form of looser types of cooperation, such as the open method of coordination and benchmarking, allowing domestic actors more control over the Europeanization of these policies onto the member state. We elaborate on this speculation in the conclusion and believe that it should be part of the future research agenda of the third wave of European research. This book emerged from the European Research Colloquium of the Netherlands Institute of Government, in which a small group of researchers from the Netherlands, Germany, Belgium, and Denmark met every 6 months over the past three years to debate substantive topics, the choice of research design and methodology, and, in particular, the empirical research presented by each author in this book