In the wake of the Balkan wars, the EU has worked hard to close the so-called 'capabilities-expectations gap' in the European Security and Defence Policy (ESDP). With the institution of new political and military structures and procedures, the agreement on principles for consultation and cooperation with other international organizations, the adoption of an acquis sécuritaire, and the launching of twenty ESDP operations, the EU has affirmed its operational capacity in ESDP. The proliferation of the EU's institutional and operational mechanisms to manage crises on its doorstep and farther afield has led to a whole series of new legal and policy questions, which were addressed at the 37th edition of the T.M.C. Asser Institute's Colloquium on European Law in 2007. The contributions by leading academics and practitioners to the Asser Colloquium have been expanded and updated in the light of the Lisbon Treaty and are now available in this unique compilation.