The terrorist attacks in Madrid and London underlined the fact that Europe is not spared from transnational jihadist terror and that its counter-terrorist efforts cannot be confined to remote regions like Afghanistan. On the contrary, European countries have become battle zones in a struggle that will remain a central moment of international relations in the years to come. This struggle poses a number of new challenges in diverse fields such as banking, information and communication technologies, or judicial co-operation and even though terrorism is no new phenomenon within the shores of Europe, both the Union and its member states have been struggling to find adequate approaches to it. In the edited book "Europe and Transnational Terrorism" a number of leading experts in the field of terrorism research assess the threat to Europe and analyze counter-terrorist policies at Union and member state level. The articles cover the threat of al-Qaeda and homegrown jihadist networks, the risk of terrorist attacks with weapons of mass destruction, the counter-terrorist policies of Great Britain and Germany, transatlantic co-operation in homeland security, the Union's efforts to combat terrorist financing, and the possibility of deterring terrorist acts.