The word 'legitimacy' is seldom far from the lips of practitioners of international affairs. The legitimacy of recent events - such as the wars in Kosovo and Iraq, the post-September 11 war on terror, and instances of humanitarian intervention - have been endlessly debated by publics around the globe. And yet the academic discipline of IR has largely neglected this concept. This book encourages us to take legitimacy seriously, both as a facet of international behaviour withpractical consequences, and as a theoretical concept necessary for understanding that behaviour. It offers a comprehensive