9/11 and its aftermath helped make more visible divergent transatlantic approaches to the legitimacy of military intervention, the utility of 'coalitions of the willing', the effectiveness of regime change and the use of coercive force within the international system. The Iraq War and the strategic dissonance it generated led many to warn against the danger of transatlantic strategic divorce, and push for transatlantic strategic realignment. The book is structured around an analysis of five Europes - 'Atlantic', 'Core', 'New', 'Non-Aligned' and 'Periphery' - which appeared to have consolidated in this period. It argues that transatlantic strategic dissonance will be an enduring feature of the Euro-Atlantic security environment as it reflects economic and military power differences, the shifting values and identities and the policy and institutional preferences of all five Europes and the US. The book concludes by arguing that transatlantic strategic dissonance and a divided West contains the potential to constitute a viable platform for the constructive management of the global security agenda, as well as regulate relations within this security community.