This book presents a conceptual history that offers a reconstruction of the concept of emancipation as it has developed within the tradition of Critical Theory and Critical International Relations Theory. It meticulously details the emancipatory content of a number of related theorists in the critical tradition, providing both an exegesis of their individual thought and the school as a whole from which its project of emancipation has been constructed. The volume moves chronologically in its study, beginning with chapters on Kant, Hegel, Marx and the Frankfurt School in Part I and on into Critical International Relations Theory and such writers as Linklater, Cox, Booth, Wyn-Jones and Held in part II. As the volume reconstructs the project of emancipation within Critical Theory, it identifies as its key limitation the under-developed nature of its cosmopolitan imagination and its lack of reflection on the importance of relations of intersubjectivity in world politics. This book will be of interest to students and scholars of International Relations, International Critical Theory and Political Philosophy.