Readers of this volume may benefit from the following context (which is not incorporated in the editor's introduction). ‘Indian Ocean (World)’ (IOW) studies emerged in the wake of Fernand Braudel's landmark La Méditerranée et le Monde Méditerranéen à l'Époque de Philippe II (1949). It has flourished as a field of study, to the extent that studies of the terraqueous worlds of the Indian Ocean have flowed into – or else elided with – the more ‘mainstream’ frameworks of imperial and colonial, world and global histories. Any unity of the IOW as a concept and space of analysis evident in the early works has been eroded by the proliferation of scholarship, much of which has examined discrete spaces of movement and exchange within the Indian Ocean; others dispelling the IOW concept altogether, so ingrained and acceptable has it now become to study the sea as a vector of interactions and circulations of people and ideas, goods, capital and technologies, not least in the longue durée. What, then, does the present volume bring to the field?

The first innovative contribution is the volume's chronological framework. Scholars have lately challenged their predecessors’ tendency to assume that the IOW changed fundamentally after the colonial transition from c. 1750 (a shift not noted in the editor's introduction), and, thus, this volume makes the point of examining the IOW in the nineteenth century. René Barendse's excellent chapter completes the volume in this spirit, examining port cities in the Gulf and Red Sea during the c. 1720–c. 1840 period of empire building, retrieving and emphasising the critical role of Asians in this process, and concluding that the IOW became both more unified in the subsequent ‘age of steam’ and more Indocentric. Mariko Fukuoka's chapter on Germans in the eighteenth- and nineteenth-century IOW converses – even if the author does not acknowledge this – with a disparate but nonetheless growing body of work that has seen empires as porous and that has sought to trace the role and agency of Germans in other European imperial spaces, including the ‘British lake’ that was the nineteenth-century IOW.

Yet, more valuably, the present volume also deepens studies of the IOW in the medieval, ancient and pre-historic periods, much as Zoltán Biedermann and Alan Strathern's edited volume, Sri Lanka at the crossroads of history (2017) has also lately sought to do. And, in complement to such chronological elongation of IOW studies is the geographical, with the space of analysis reconceived as a larger Asia-Pacific terraqueous ‘terrain’ of interaction. Pierre-Yves Manguin's elegantly written chapter navigates the reader through the debate on the ‘Indianisation’ of Southeast Asia, drawing upon (recent) archaeological evidence to demonstrate the much earlier commencement of exchanges across the Bay of Bengal, starting at least in the late prehistoric and proto-historic periods. If this and Ranabir Chakravarti's contribution, outlining Indic commercial networks (c. 500–c. 1500), highlight the roles of India and Indians, a greater number of chapters in this volume illuminate China's importance to the IOW. Angela Schottenhammer, Hyunhee Park and Alexander Jost's chapters all examine the ebb and flow of Chinese trade across the IOW from the ancient to late medieval periods. John Chaffee and Manel Ollé’s chapters on foreigners in Chinese ports and the Chinese merchant diaspora in the Philippines, respectively, examine interactions resulting from seaborne connections up to the early modern period. Don Wyatt's chapter examines Chinese involvement in the trade of slaves and goods from East Africa. Other chapters, such as John Guy's exploration of Arab dhows found in Southeast Asian sites that shows the long-distance connections across the IOW in the first millennium, demonstrate the agency of other communities – Arabs and Persians – and their respective ‘home’ spaces.

Just as the unity and utility of the IOW framework have been lost as the field has flourished and expanded, so, too, is the contribution of this volume lost in the multitude. At times, the volume loses focus, the inclusion of chapters on official and contraband trade – by Om Prakash and Ichiro Ozawa – veering it onto an unexpected tangent, for example. Had the book included only those chapters examining China's place in the IOW, placing them in dialogue with recent work – for example, Zheng Yangwen's China on the sea (2011) – revising the narrative of a China sealed off from the world, this volume would be a much clearer and coherent contribution to current debates, balancing an Indocentric with a Sinocentric IOW while reflexively making clear the role of maritime exchange in Chinese history. In addition, had the editor written a longer introduction, knitting together the multifarious contributions within the yarns of the existing scholarship, the volume would have stood as a more useful product – for students and scholars as well as specialists – than a mere record of the papers presented at a conference. Instead, a great deal is expected of the reader in terms of their familiarity with the state of the art in IOW scholarship, their ability to connect together the strands threaded (implicitly) through the chapters and between the chapters and other larger historiographies, and their interest in an extraordinarily diverse range of topics to merit persevering with a volume (the first of two?) extending to almost 400 pages.