Our main question in this book is “What drivers and mechanisms of institutional change are present in Europe and East Asia?” Three sub-questions focused first on the relation between top-down regionalization and bottom-up regionalism, secondly on domestic and external factors of institutionalization, and finally on long-term developments related to the nation-state, regionalism, and regionalization. In this chapter, we will give an answer to these questions. We will conclude the chapter with some remarks about the increasing relevance of Asia.