Organized Crime and Terrorist Networks (OC/TN) are a major challenge for the European Union and many different stakeholder groups are involved in creating awareness, preventing, identifying and intervene in case of risk or threat. But in order to develop better strategies and instruments, we still need a deeper understanding of these phenomena. TAKEDOWN therefore aims at generating such novel insights on OC/TN. In order to meet this challenge and to investigate this complex field of research a multidimensional modelling approach is used. The resulting, proprietary TAKEDOWN Model describes social, psychological, economic aspects as well as further dimensions, activities and response approaches. A comprehensive empirical research combined with European and international expert knowledge ensures a valid and intuitive model.