Are terrorists idealists acting on the spur of solidarity or are they outlaws killing innocent people and damaging property in order to change policies, even if they are democratically agreed upon? And why do people become terrorists? Can their behavior be explained upon the basis of their social context or is it their personal mindset that makes them apt for terrorist behavior? And for how long does one stay a terrorist. Is being a terrorist part of a youth culture or can one be a lifelong terrorist? Bob de Graaff, professor for terrorism and counterterrorism of The Hague Campus of Leiden University, will present some historical cases to determine whether terrorists are actually idealists or criminals and whether dialogues and negotiations with terrorists are an option for governments or not. In passing he will address the question whether historical lessons are helpful to understand current terrorism and counterterrorism policies.