In recent years the EU has been emerging as a significant diplomatic actor on the international scene. However, in spite of its treaty-based aspirations to act coherently and effectively in external action, the EU has remained a rather confusing actor for third parties throughout its development. In times of a ''transformational diplomacy,'' an ''interpolar world,'' and profound global challenges, the Lisbon Treaty has laid the groundwork for further development of an even wider system of EU diplomacy, which has helped to provide new momentum for the architectural diplomatic actorness of the EU in the world. On the other hand, there have been doubts expressed about its potential to deliver coherent and effective policies in order to meet the demands of an increasingly complex world. This book investigates whether this new system of EU diplomacy will provide the EU with the institutional capabilities that will enable it to perform a more coherent and effective diplomatic role in the world arena. The book is intended for readers who have a specific interest, among others, in EU diplomacy and foreign policy as well as its institutions.