This book was originally published by Claeys and Casteels, now formally part of Edward Elgar Publishing.For almost 400 years, under the Westphalian system established in 1648, the classic notion of sovereignty has been the pillar of the international relations among States free to do what they want within their territory with the prohibition of intervention in one another’s affairs. Humanitarian crisis, international terrorism, weapon of mass destruction, failed states, pandemic, the increasing role of regional and international entities, ONG and financial entities have eroded the tenuous boundaries between the domestic and international notion of sovereignty.Sovereignty no longer provides protection to the State which to survive must cede some power in order to cope with the challenges of the new international order. However, despite the increasing number of actors in the international arena and the identity crisis of the notion of sovereignty, the State is bound to remain the lead actor on the global stage and, in this light, sovereignty can emerge stronger, provided it fully incorporates its responsibility towards the its own people and the entirety of the international community.