The way in which terrorism is countered results from perceived or actual insights of state security authorities. That their approach is by no means always optimal is evident, for example, in the NSU case, which revealed that the greatest weakness of German extremism expertise was the failure to consider the concept of a leaderless organized terrorist cell. The global expansion of jihadism and the alarming fact that Al-Qaeda has been surpassed by an even more brutal movement called the Islamic State also do not necessarily indicate the success of the ongoing war against terrorism. The aim of this volume is to provide an informative overview of the goals, strategies, and dangers of terrorism on the one hand, as well as possible and we.