With the new wave of terrorism, many questions have been raised by scholars, politicians, members of the military, and even ordinary people, all of whom have been startled by this extreme kind of violence. Questions have been raised about terrorism as a phenomenon, but also about the possibility of defeating it. Not surprisingly terrorism has become the top priority of most governments, security agencies, intelligence services and military establishments. One of the questions that the authors who contribute to this book try to answer is whether just war theory is outdated in this time of terrorism. But they also deal with several other closely related questions such as the acceptability of so-called pre-emptive and preventive strikes, and the role of the UN, NATO, US and Europe in the international fight against terrorism. With its interesting spectrum of viewpoints on some very actual and challenging themes, this book attempts to challenge the personal opinion of scholars and other interested readers.