In the age of global politics, nation states have become emeshed in a web of multiple and interconnected layers of authority, where decisionmaking powers have been transferred to international and supranational organizations . This shift has led to new debates concerning issues of legitimacy: are western democracies and their core institutions, primarily parliaments, faced with a legitimacy crisis? How legitimate are emerging international governance structures? And how is it possible to test legitimacy? In this collection, scholars from political theory, comparative politics, and international relations explore the conceptual and methodological issues of legitimacy in an era of globalization. The volume provides an overview of the frontiers of normative and empirical legitimacy research and provides the foundations for an integrated, multi-dimensional perspective on legitimation processes.