The presence of Great Powers and outlaw states is a central but under-explored feature of international society. In this book, Gerry Simpson describes the ways in which an international legal order based on 'sovereign equality' has accommodated the Great Powers and regulated outlaw states since the beginning of the nineteenth-century. In doing so, the author offers a fresh understanding of sovereignty which he terms juridical sovereignty to show how international law has managed the interplay of three languages: the languages of Great Power prerogative, the language of outlawry (or anti-pluralism) and the language of sovereign equality. The co-existence and interaction of these three languages is traced through a number of moments of institutional transformation in the global order from the Congress of Vienna to the 'war on terrorism'.