For a long time our textbook knowledge of what is happening in the Council of the European Union -- the major decision forum of the EU -- was to a large extent based on limited interview-based evidence. One reason for that was the closed nature of the Council. In a very few years, however, thanks to new transparency rules and increased efforts by scholars, we have seen a whole range of superb qualitative and quantitative data collections as well as more convincing theorizing. EU researchers are better equipped than ever before to analyze the decision-making processes of the Council and to test conventional wisdoms. The effect will be important, not only with respect to our knowledge of the Council itself -- and therefore of EU politics in general -- but also because this research is advancing general theories about how government interact in international institutions, for which the Council is a particularly fruitful object of study. This book covers the most contentious areas and important debates in the present research, focusing in particular on conflict dimensions, modes of interaction and power and leadership in the Council.