Transatlantic security cooperation has developed into a hybrid object. This necessitates a look beyond the two institutional cornerstones of cooperation, NATO and the bilateral EU-US relationship. The book addresses the historical and current conceptions of transatlantic security relations and analyzes new ‘platforms’ for cooperation such as the EU-3 initiative in regard to Iran, various forms of EU-NATO cooperation as well as the Middle East Quartet. The contributors examine the member states’ perspective on the relationship and discuss some new areas for action including a CFSP caucus in NATO, a reversed Berlin-plus agreement, a «Joint Transatlantic Nation-Building Task Force», and common criteria for stability operations on both sides of the Atlantic. The message throughout the book: there is no ‘master plan’ for strengthening transatlantic relations, but strong reasons to move forward with a sense of pragmatism.