Ten years after the September 11th terrorist attacks, the strategic options of the West in modern warfare have fundamentally changed. Terrorism has not only proved to be a consistent phenomenon, but also just one facet of global security challenges. On the one hand, the pattern of “new wars”, where with fragile statehood governments no longer have a monopoly on the use of force, has dominated the conflicts of the last decades. On the other hand, various types of warfare, meaning regular, irregular and terrorist, appear to amalgamate into a new type of warfare, the “hybrid wars”. This book delineates the Western strategic options in “hybrid wars” with a holistic analysis of three interdependent considerations. First, the question of “where” to intervene addresses the contemporary threat scenarios. Second, the question of “why” to intervene affects the right and interests to use force. Third, the question of “how” to intervene covers the military options and the logic of strategy. After a theoretical introduction, the historical cases of Somalia, Rwanda and Lebanon serve to depict the Western room for manoeuvre in the 21st century.