John Broich's Squadron reflects a growing interest in nineteenth-century British efforts to suppress slave trafficking beyond the Atlantic, which has tended to dominate historical discourse on the issue. As its short title suggests, it is essentially a study of British naval action against the East African slave trade. For that reason, it is likely to attract particular attention from maritime historians as well as those interested in slavery and abolition. But Broich's approach and sources give his book even wider historical resonance, for he explores how British policy was shaped and how slave trade suppression strategies affected British imperial relations in the western Indian Ocean. In these respects, his book has greater range and significance than its title suggests.

Zanzibar-based Arabs and Indians dominated the East African slave trade in the period of Broich's study, supplying slave markets from the Red Sea to the Persian Gulf. Among Britain's moves to close this trade, the mission of Sir Henry Bartle Frere, a former governor of Bombay and India, to the sultan of Zanzibar in 1873 has rightly been accorded prominence. Its goal was to stop the flow of enslaved Africans from the mainland to Zanzibar, where slaveholding was legal but from where captives might be reshipped by dhow northward to the Middle East. Reinforcing the mission was a decade-long naval blockade that effectively closed Zanzibar's slave market. Slavery remained legal in Zanzibar until 1897, but the Frere mission marked, according to Broich, “the beginning of the end of the East African slave trade” (256). Broich's principal concern, and what gives his book its significance, is his depiction of suppression policy's larger imperial context and the role that naval intervention before 1873 played in influencing Liberal prime minister William Gladstone's decision to dispatch Frere to Zanzibar and to initiate a blockade of the island.

Broich's treatment of these issues pivots around his discussion of the careers of four senior British naval officers based at Bombay but actively involved from 1868 to 1869 in suppression activities off East Africa. The officers concerned were Leopold Heath, the naval squadron's commodore, and captains Edward Meara, Philip Colomb, and George Sulivan. All brought considerable naval experience to their task, including prior experience of slave trade suppression in either the Atlantic or the Indian Ocean. Their logbooks, correspondence, reports, memoirs, and evidence in 1871 to a House of Commons committee on slave trade suppression constitute the book's core documentary sources. From them, we learn how the officers adapted strategy in 1868–1869 to nature and to prevailing shipping technologies. We gain insights into the mix of tedium, elation, and frustration that accompanied their endeavors to capture slave-carrying dhows, and we see the human costs on both sides of the sometimes violent engagements between the Royal Navy and its quarry. This was emotive, highly charged human history, and Broich's writing draws it out well. The most telling revelation, however, and the one that ultimately, Broich argues, lay behind the Bartle Frere mission of 1873, is the zealousness, at time even combativeness, with which the four officers pursued their cause. It was expressed in their cavalier use of stop-and-search of dhows at sea or near port on the pretext that they might have slaves on board; in decisions to destroy dhows with Africans aboard, even when these passengers’ status was questionable and their numbers very small; and in their willingness to offer refuge to runaway slaves who were deemed the legitimate property of land-based African owners. One might interpret such behaviors as driven by the bounty system identified with slave-carrying dhow hunting. A more charitable, perhaps more accurate, view would see them as manifestations of religiously based, humanitarian convictions on the part of the four officers. Yet, behind such motives, Broich detects a deep frustration among the naval officers studied. It reflected in part their modest rate of success in liberating trafficked Africans at sea. It reflected, too, a belief, based on experience on station in 1868–1869 and articulated in 1871 in evidence to the House of Commons, in the incompatibility of accepting the trafficking of slaves from mainland Africa to Zanzibar to sustain the island's plantation economy with British efforts to suppress shipments of slaves from the island to markets in the Middle East.

The immediate political response in London and Bombay to suggestions that British naval officers were overzealous in pursuing suppression activities was to tighten the rules governing the naval squadron's behavior on station and to recall the four principals involved. Their recall, however, provided opportunities for Heath and his fellow officers from 1870 to 1873 publicly to air their experiences of and frustrations with the limited efficacy of slave trade suppression in practice. In Sulivan's case, it was through publication of a memoir about dhow hunting in Zanzibar waters. In Heath's and Colomb's, it was through testimony to a House of Commons inquiry in 1871, where they urged intervention to stop the flow of slaves into Zanzibar from the mainland as a prerequisite for delivering a successful anti-slave trade campaign in East Africa. Their advocacy of a change in British suppression strategy, which was ultimately manifest in Bartle Frere's mission and the blockading of Zanzibar, was echoed in press reports of the heroism, sacrifices, and frustrations of those charged with suppressing slaving. It perhaps gained unanticipated support from news of Henry Morton Stanley's discovery of the explorer David Livingstone in November 1871 at Lake Tanganyika. Hostile to slavery, Livingstone is said to have hoped to use his fame from discovering the Nile's source as a means to speak with power to men and thereby “remedy an immense evil” (Tim Jeal, Livingstone [2013], 289). But it is perhaps not too fanciful to suggest that in speaking truth to power in Britain between 1871 and 1873, naval officers Colomb, Heath, and Sulivan, with their firsthand experiences of Africa and slavery, did as much as, if not more than, Livingstone to initiate a new chapter in British policy towards slave trade suppression in East Africa in 1873. Sulivan's appointment in that same year to a leading position in the blockade of Zanzibar adds substance to the idea, underscoring the significance of Broich's book, which makes a valuable contribution to our understanding of the evolution of British antislavery practice and its links to imperialism from 1870 onward.