"Why do international orders lack systemic legitimacy? This study examines the developing relationship between the US and China and explores the ways in which these two global powers are transitioning to a new global order, albeit one with significant risks and uncertainties for governance and legitimacy. Terhalle argues that the financial crisis of 2008/09 established China as the key challenger to the United States amid a process of order transition. Subsequent disagreements between these two powers about the future shape of the global order's legitimacy have manifested themselves in their intense competition with regard to spheres of influence in East Asia and the environment and ideology-related aspects of the order. In positing a new theoretical framework for understanding order and legitimacy in International Relations, The Transition of Global Order offers a significant contribution to the debate around world politics and the new global order"--