Foreign fighters and homegrown terror have become two of the most salient political concerns in Europe this year. European Islamists – both those who have travelled to fight in Iraq and Syria and then returned to their countries, as well as radical al-Qaida and ISIS sympathizers who never left home – present an ever increasing and more difficult to control danger to homeland security. The growing debate on how to address this phenomenon in Germany and Europe more broadly has raised questions of extreme relevance not only to security authorities, but also politicians and civil society: What motivates young Europeans to join the so called “holy war” in the Middle East? How can authorities prevent more and more jihadists from leaving Europe to travel to Syria and Iraq? What mechanisms can be put in place to effectively monitor those fighters who return, in order to prevent terror attacks on European soil? How can government and civil society work together to defend the safety and values of Europeans against radical Islamist terror?