Perhaps more than any other aspect of the transatlantic slave trade, the middle passage exposed the tensions inherent in trying to turn humans into commodities. On the one hand, merchants packed slaves in vessel holds in ways that resembled the shipment of tobacco, rum, and the other non-human goods that dominated pre-20th century transatlantic commerce. On the other, the very real threat posed by slave rebellion - and the care that owners and operators of vessels took to prevent such uprisings - made clear the unique nature of the cargo that slave vessels carried. It was this tension in particular that drew fire from abolitionists in the late-18th and 19th centuries, and that has helped the middle passage maintain its cultural significance in the western world a century and a half after the last slave ship crossed the Atlantic. Indeed the middle passage was such a central part of the American slave experience that it would be difficult to imagine the crossing outside of a western historical context.
Yet this is precisely what Many Middle Passages forces its readers to do. Gathering scholars at a conference in Fremantle, Australia, in 2005, the editors encouraged contributors to consider how the transatlantic middle passage could illuminate new avenues of research in relation to the coerced movement of people in different historical and geographic settings. The result is a rich volume of essays that provides many new and interesting details about the transportation of unfree people in the abolition and post-abolition eras. In a thought-provoking introduction, the editors skillfully weave together the various contributions to reevaluate the concept of the middle passage itself. Not content with strict maritime definitions, the authors propose a broader theoretical approach in which the passage forms "the structuring link between expropriation in one geographic setting and exploitation in another" (p. 2). This inclusive definition provides a crucial element of unity for a volume that covers a striking variety of settings and degrees of coercion. In this sense, Many Middle Passages joins works by scholars such as Patrick Manning, David Eltis and others in applying a broad comparative framework to the study of forced migration, bridging the divide between the study of the slave trade and other systems of unfree labor .
The volume itself consists of 11 chapters plus an introduction, an afterword and an original poem written by Markus Rediker as a postscript. The sheer number and diversity of contributions makes this collection particularly difficult to review. With one partial exception, the volume is concerned only with the non-Atlantic world and covers the trafficking of slaves, convicts, indentured laborers, and to a lesser degree women and children involved in the sex trade. Three chapters focus primarily on Africa. Ned Alpers and Iain McCalman treat complementary aspects of the East African slave trade and British attempts to suppress it in the second half of the 19th century. Alpers uses testimony from enslaved children to illuminate slave experiences with the Indian Ocean middle passage. McCalman argues convincingly that although David Livingston's Zambesi expedition in the 1850s and 60s failed to identify a suitable location to establish a British colony, it nevertheless exposed a major internal slaving network and provided the British Foreign Office with a blueprint for how to disrupt this traffic. Nigel Penn rounds out the treatment of Africa with an assessment of German migration to the East Indies on Dutch East India Company vessels, drawing on Peter Kolb's well-known account of the Cape settlement from 1719.
The other contributions turn to coerced migration in the Southeast Asia/Pacific region, if we define the area broadly. China is particularly well represented. Scott Reynolds Nelson provides a comparative study of Irish and Chinese migration to the eastern and western United States respectively during the Civil War and in its immediate aftermath, where migrants worked on railways and in the military. Evelyn Hu-DeHart shows how growing demands for Cuban sugar, Peruvian cotton and guano, and to lesser extent Australian minerals drew European and American entrepreneurs into Macao and Hong Kong in search of Chinese laborers. Julia Martínez's chapter charts changes in the scope and organization of the traffic in women and children around the China Sea over the last century and a quarter. James Warren extends his earlier work on slaving in the Sulu Archipelago in Southeast Asia, linking European commercial expansion into China with changing local and regional demands for labor in the Sulu Zone. Clare Anderson's chapter analyzes the shipment of criminals from India to penal settlements throughout the Indian Ocean, paying particular attention to shipboard resistance on these voyages. Cassandra Pybus and Emma Christopher tackle the early transport of British criminals to Australia, while Laurence Brown's analysis underscores the fluid nature of the labor trade in the western Pacific, where enslaved and contract labor systems interacted and overlapped.
Viewed as a whole, the volume has several structural tensions and a few other flaws, which are perhaps inevitable in a work of this nature. The title of the book is misleading in two senses. Of the 11 chapters, only one explores post-1900 issues in any depth. It is possible that the transformations in systems of coerced migration described in this volume provided a foundation for the making of the modern world, as the title implies, but the issue of continuity over time is assumed rather than assessed. Moreover, as most of the authors note, distinguishing between coercion and freedom is no simple task. Julia Martínez captures this sentiment when she notes that "a woman's journey might begin with some degree of consent and end in slavery" (p. 217). However, several contributions use the concept rather loosely. One wonders, for example, about the extent to which Peter Kolb's account - which details his passage to the Cape settlement under the patronage of the mayor of Amsterdam to "undertake observations of the heavens" - can be used to represent the experiences of German bondsmen traveling to the Cape for military service. Finally, the maps do not do the volume justice. Several points or entire regions that are discussed in the text are not represented. China is entirely unlabeled.
 Patrick Manning ed., Slave Trades, 1500-1800: The Globalization of Forced Labour (Aldershot: Variorum, 1996); David Eltis, ed., Coerced and Free Migration: Global Perspectives (Stanford: Stanford University Press, 2002).