Andrew Phillips is an Australian Research Council Discovery Early Career Research Award Fellow and Senior Lecturer in International Relations and Strategy in the School of Political Science and International Studies at the University of Queensland. J. C. Sharman is a Professor in the Centre for Governance and Public Policy at Griffith University.

• Introduction; 1. The puzzle of durable diversity in international relations; 2. The initial growth of diversity, 1500–1600; 3. The expansion of diversity and competition under heteronomy, 1600–50; 4. The stabilization of diversity, 1600–1750; 5. Reconfiguring diversity in the age of empire, 1750–1900; Conclusion: order in diversity.

'This superb historical sociological exploration of the Indian Ocean system in effect provides a compelling and vitally important double-provincialisation of Westphalia: first, by revealing how heteronomous rather than (Westphalian) homogenous international orders have constituted the norm in world political history; and second, by revealing the critical point that the standard Westphalian logic of homogenization reflects a Eurocentric conception that simply does not stand up when applied to the non-Western world.' John M. Hobson, University of Sheffield