At a time of unprecedented turmoil in the transatlantic relationship, this book addresses a number of the key security challenges that confront decision-makers on both sides of the Atlantic. The contributors examine the widening divergences in Western threat perceptions and investigate religiously motivated terrorism as both a socio-political phenomenon and as a security threat. The risks and unique challenges posed by the proliferation of Weapons of Mass Destruction are examined and the viability of new arms control and disarmament regimes to tackle these dangers is assessed. Finally, the book examines what the impact of the post-9/11 security environment has been on the evolution of both NATO and the European Security System. The book explores whether NATO is losing or radically changing its traditional role of collective defence organization after the war in Iraq. Will the war on terrorism reinvigorate NATO, or will it merely become a convenient military 'toolbox' for the United States to dip into to construct 'coalitions of the willing'? The book also examines what the future prospects are for creating an effective and worthwhile European Security and Defence Policy that would enable Europe to play a full international role as partners of the US.