To Karl Marx, under capitalism, exchange is an all-embracing presupposition that ineluctably creates an ever-widening sphere of circulation: “Every limit appears as a barrier to be overcome” (Grundrisse, trans. M. Nicolaus [1973], 407–8). Johan Mathew's sterling book traces this dynamic at a formative period of modern capitalism. It takes as its focus the Arabian Sea in the period from the 1860s to the 1950s, a time traditionally seen as marking the integration of Asia and Africa into a Eurocentric capitalist world system. This work, by contrast, takes us beyond the official attempts to delimit and control the region's commerce to the merchant networks that evaded, subverted, and challenged such confines. In the process, Margins of the Market not only makes an important contribution to our understanding of the intermingled histories of trade and empire in the region, but also offers an astute reflection on the theoretical constructs of capitalism.

In the nineteenth century, Britain was the dominant power in the Arabian Sea. The transition in 1858 from Company rule to Crown rule in India brought with it the abolition of the last mercantilist policies. Rather than as a trading party in its own right, Britain now sought to serve as the guarantor (and chief benefactor) of a regime of “free trade” that it imposed and enforced across the seas. It was during this period that the British gunboat became a dominant emblem of capitalism, forcing open borders to international trade and striking down inimical tariffs. As Mathew points out, British efforts in the Arabian Sea differed from this general mission. Rulers along its coastline were already generally open and friendly to foreign trade, leaving the British in a role of regulating trade. In the Arabian Sea, Britain's “free trade ideology” was primarily implemented through its intervention in local markets and through the abolition of certain trades (p. 6).

Mathew's book traces the history of this intervention—and, alongside it, of its underlying ideology—through case studies of three commodities that the British made particular efforts to control: slaves, weapons, and gold. Each of these presented special challenges not only in practical terms but also conceptually. The ensuing “elaborate dance” between bureaucracies and merchants, between regulation and circumvention, that characterized the trade in bodies, guns, and coin across the Arabian Sea extended from the goods themselves to the very notions of laissez-faire and trafficking, of licit and illicit commerce (p. 176). A final chapter expands on this theme by tracing the effects of the Marginal revolution in the trading world of the Arabian Sea, which again shows a contentious interaction over capitalist categories (in this case, the meaning and measure of “real value”) between colonial officials and local commercial interests.

What emerges from these case studies is the sense of an ongoing contest between government bureaucrats responsible for defining and policing the boundaries of capitalism and merchants engaged in testing, bending, or breaking these limits on free enterprise. Mathew argues that this struggle is not incidental to but rather “constitutive of capitalism itself” (p. 2). This claim is lent credence by the author's sustained effort of moving between the realms of political economy and intellectual history on the one hand and the complex and often contradictory evidence from the Arabian Sea on the other. The book is, above all, marked by a masterful engagement with this evidence, which, like a dhow propelled by the monsoon winds, navigates nimbly between different languages, regions, and contexts. Moving from quantitative data sets to the “almost ethnographic” accounts of trafficking found in colonial surveillance records and court transcripts, from European business records to the correspondence of Indian merchants, from imperial policy briefs to Islamic fatwa collections, Mathew manages to recreate a sense of the diverse, dynamic, and often intractable commercial environment of the Arabian Sea (p. 16).

To the reader of this book, it can come as no surprise that it was awarded the 2017 Ralph Gomory Prize of the Business History Conference. Margins of the Market is business history at its finest: conceptually ambitious, empirically grounded, and a pleasure to read. It makes significant interventions in the study of Arab-Indian trade diasporas, of unfree labor in the Indian Ocean, and of the development of European business enterprises in Asia (which, in their reliance on imperial patronage and diasporic arbitrage, came to look a lot like the local firms they were meant to supersede). Most importantly, though, it provides an original, subaltern addition to the history of capitalism. By contextualizing the development of capitalism within the specificities of the Arabian Sea, a region otherwise often seen as only peripheral to the progress of the twentieth-century world order, it broadens our understanding of how this world order emerged outside of its core areas: uneasily, unevenly, and in unexpected forms.