Book excerpt: Brexit confirms that the EU is not a super-state in the making but rather an advanced regional organization. This book bridges the gap between EU studies and international relations by providing a student-friendly presentation of regional, multidimensional cooperation among neighbouring states and societies, its four epochs and relevant variations and similarities across five continents, its interplay with globalization, and the changing post-hegemonic and post-Cold War international order. This text secondly focuses on the question of regionalism in hard times: whether the global financial crisis and multipolar power politics are leading to more competitive and political forms of instrumental regionalism and interregionalism in Europe, East-Asia and the Americas. It does this by addressing the political and strategic dimensions of changing regional/interregional arrangements and their current and potential impact on global governance, notably on trade and security challenges.