Historians of slavery are now coming to recognize that the massive scholarship on the scale and impact of the trans-Atlantic slave trade has inhibited awareness of slavery and slave trading elsewhere in the world, and especially in the Indian Ocean. At the same time, earlier neglect of the Indian Ocean in maritime studies, in comparison to the Atlantic (and indeed to the Mediterranean and Pacific), is also beginning to be redressed.

Richard Allen has been at the forefront of both developments through his books and key journal articles, as well as editor of Ohio University Press’s new Indian Ocean Studies series. European Slave Trading in the Indian Ocean marks a new stage of his scholarship by arguing that Indian Ocean slavery and slave trading was a key component of slavery in the wider colonial world and in the debates over its abolition. Allen recognizes that there is much still to be done and, in some respects, the book reads as a series of disconnected chapters and themes rather than an overall synthesis. It does not claim to be a study of slavery in the Indian Ocean as a whole but, instead, focuses on European trading interests and plays to Allen’s specialized interest in the Mascarenes with new material drawn primarily from the India Office records.

Nonetheless, it will become a standard work in the field and for several differing reasons. Firstly, as claimed by David Richardson on the back cover, it seeks to do for the Indian Ocean what Curtin did for the Atlantic, to estimate the scale and directions of European slave trading over a period of 350 years. This is an even more difficult task than it was for the Atlantic since there were relatively few specialized slave merchants or ships and thus no set of comprehensive shipping records. Nonetheless, Allen succeeds especially in breaking down the compartmentalized view of slave trading by differing European trading companies or national states and by redressing the domination of Dutch trading in the existing literature. This is particularly so for the eighteenth century, for which data is provided in statistical appendices. The result is an estimate of around 1 to 1.2 million slaves directly traded by Europeans in the region between 1500 and 1850, a figure considerably lower than that of the Atlantic slave trade in the same period, but nonetheless one of significant scale.

Secondly, Allen stresses that this trade was closely inter-linked to the Atlantic world since the Indian Ocean did not exist in a self-contained bubble. For instance, St. Helena, the Cape of Good Hope and the networks of the south Atlantic played a significant role in the establishment of a trading and colonial settlement system in the south-western Indian Ocean, which in turn through the Mascarenes was connected to India and the labour recruitment systems of South and Southeast Asia: “the Mascarenes were at the centre of a dynamic slave-trading network that stretched not only from one end of the Indian Ocean to the other but also deep into the Atlantic” (67). Slaves from East Africa and Mozambique, shipped via the Mascarenes and around the Cape, formed an increasingly significant part of the south Atlantic slave trading system between the 1770s and the early nineteenth century. Madagascar was central in linking pre-colonial slave trading networks to firstly Dutch and then French and British colonial interests in ways which place Indian Ocean trade “in larger, more comprehensive contexts” (103).

Thirdly, Allen’s focus on the Mascarenes enables him to link developments in the southern Indian Ocean and Atlantic to the Indian sub-continent. The use of Indian slaves there (prior to and alongside the introduction of much better-studied indentured labourers) leads him to discuss the position of slavery in India and its trading connections to Southeast Asia. Allen also makes a convincing case for linking slave trading to networks of convicts and indentured labourers in the nineteenth-century Indian Ocean, thus breaking down the somewhat artificial divides between differing forms of forced and unfree labour and connecting his findings to recent important scholarship on such labour systems in the colonial Indian Ocean world. This also points to the neglected inter-relationship of slavery with convicts and indentured labourers in the Atlantic, connections that the salience of race in studies of slavery has underplayed.

Finally, and perhaps most strikingly, the final chapters make the argument that developments in the Indian Ocean profoundly affected debates about abolitionism more widely in the British empire and further afield. The role of the East India Company in highlighting the existence of slavery in India and beyond played a significant part in debates around abolition of the slave trade in Britain and, as a result, “India was no less a centre of abolitionist sentiment and activity than Britain during the late 1780s and early 1790s” (182). Although notoriously slavery was not ended in British India at the time of its abolition elsewhere in the 1830s, Allen shows how the ongoing discussion around its role continued to feed debates over a range of forms of unfree labour in the mid- and later nineteenth century. Allen thus argues that “historians of slavery and abolition can no longer turn a blind eye to what was undoubtedly a complex dialogue between the forces of abolitionism in Indian Ocean and Atlantic worlds” (210).

These factors all make European Slave Trading in the Indian Ocean a highly significant work. It does lack cohesion in some places and is sometimes burdened by minutiae which detract from the central arguments, in particular regarding Allen’s specialized area of Mauritius in the abolitionist period. It also lacks any sense of the perspective of slaves themselves, since its focus is on Europeans as traders, colonists, and abolitionists. This is a marked contrast to recent Atlantic studies of slave trading and may reflect the fact that Indian Ocean writing on the topic is at a much less developed stage than its Atlantic counterpart. But such work does exist and will doubtless continue to burgeon, and it will be largely a tribute to the pioneering scholarship of Richard Allen when it does. He would the first to agree that this book is not the final word on its subject, but it is undoubtedly a highly significant milestone on the way and means that historians of the European slave trade can no longer ignore its Indian Ocean dimensions.