Transnational risks of violence such as ethnic conflicts, organised crime (drug trafficking, money laundering), or terrorism are both a cause and a feature of a transition from a national to a post-national world. Much evidence suggests that, compared to interstate conflicts, transnational violence has gained in importance and will continue to do so. Transnational risks change the interplay between sub-national, national and international actors, as these actors' roles and relative weights as both causes and managers of problems shift. The authors of this book define the phenomenon of transnational risks of violence in the context of the "postnational constellation" and examine its involvement in current conflicts, track different forms and complex entanglements of such risks and analyse the concepts, strategies and instruments that international organisations have adopted to combat transnational risks and promote security and peace.