Kosovo represents, in a nutshell, the problems created in the Balkans by past history and modern power politics. Former Yugoslavia was exemplary for an artificial State where even the division into five republics and two autonomous provinces did not satisfy the divergent aspirations of the respective nations and ethnic groups; it disintegrated as soon as communist ideology and Serb-dominated armed forces ceased to exist as a common bond. This faced the international community and its legal order with an enormous challenge. This book explores the question of how to reconcile the principle of territorial integrity of States with legitimate claims for secession in exercising the right of self-determination in general. Subsequently it focuses in detail on the special case of Kosovo, comparing the meanwhile successful independence process with the Abkhazian and Southern Ossetian matters. Beyond that the book examines the legal and political challenges for the European Union’s commitment to the Kosovo under its Common Foreign and Security Policy.