At its peak at the end of the 19th century, the British Empire ruled half the world's Muslims. Within its global empire, Britain ruled more Muslims than any other confessional group. And yet, John Slight notes, few historians have written about the British Empire as encompassing large, internally diverse, and geographically dispersed Muslim populations. Slight seeks to address this problem with this well-researched and fascinating book, a history of the British empire's interactions with the hajj, the Muslim pilgrimage to Mecca. His story begins in 1865, the year a global cholera epidemic traced to infected hajj pilgrims scared the British and other imperial powers into greater involvement in the pilgrimage. It ends in 1956, when the Suez Crisis forced the British to give up authority and control over the ritual.

Slight wants to show that the hajj was central to British governance of Muslim colonial populations across Africa and Asia. One of the five pillars of Islam and an obligatory ritual, the hajj was the single largest world pilgrimage by the late 19th century, the height of the European imperial era. Then, unlike now, it was an annual event that involved a majority of European colonial subjects (Muslims from British as well as Austrian, Dutch, French, and Russian imperial lands). The subject is enormous and Slight does a fine job framing it as a manageable global story. An elegant set of maps helps the reader orient herself in a story that spans British India, Malaya, Sudan, and Nigeria, based mainly on documents from colonial archives in the UK, India, Malaysia, and Singapore.

Through the subject of the hajj, Slight attempts to make three contributions to British imperial history. First, he argues that historians should pay more attention to imperial governance of religious practices as central to the “exercise and legitimation of imperial power” and crucial to understanding Anglo-Muslim relations in the British Empire (p. 3). Second, he wants to broaden the definition of the “British World,” a concept advanced by British imperial historians with recent books about white settler colonies and dominions (what Slight refers to as an “outer empire”), to also include an “Islamic inner empire” of Anglo–Muslim interactions (p. 3). Connected to this, he notes that the hajj reveals the categories of “British” and “Muslim” as less separate and oppositional than scholars have presumed. Third, following Thomas Metcalf's “trans-colonial framework,” Slight tries to demonstrate the “interconnectedness of Britain's Muslim empire” beyond the Indian Ocean arena (p. 7), to which other previous studies have been limited.

What exactly was Britain's “Muslim empire” and who would have experienced it as such? Slight defines it as a vast interconnected space that included the Gambia, Sierra Leone, the Gold Coast, Northern Nigeria, Sudan, Kenya, Tanganyika, Zanzibar, Egypt, Somaliland, Palestine, Trans-Jordan, Iraq, Kuwait, Bahrain, Qatar, the Trucial States, Aden, India, Malaya, Brunei, and Sarawak. His main focus is not the Muslims who lived in these regions but British colonial officials, who gradually became involved in the hajj for ever-changing reasons related to imperial geopolitics and local colonial contexts. He argues that through its engagement with and eventual administration of the hajj across Asia and Africa, Britain effectively produced a Muslim empire: “a tangible political, organizational, and religious entity” (p. 2).

Around the 1870s, reports of indigent pilgrims lying outside the British consulate in Jeddah came to be seen as an embarrassment to the empire, and colonial officials started paying for pilgrims’ passage back home. Slight argues that with the outbreak of World War I, during which British troops fought in the Arabian peninsula, the British gained a stronger sense that they ruled a Muslim empire, a network of Muslim-majority colonial territories connected by Islamic practices, with Mecca at its center. He persuasively suggests that interwar expansion of British involvement in the hajj grew from this wartime revelation, and was largely about enhancing British imperial prestige and maintaining control over its empire. During World War II, the British saw the hajj as useful to empire in another way, as a conduit through which to spread British propaganda.

Slight reveals how the British sought to tap into the hajj to further its imperial goals. He suggests this is part of a larger story of how the British tried to co-opt and benefit from other Islamic practices, but the claim remains unsubstantiated. As a central Islamic ritual that was also (by the late 19th century) a mass migratory phenomenon, the hajj may have been an exceptional case. It is also not clear to what extent the idea of a Muslim empire was widespread in the minds of British colonial officials and scholars of Islam and Muslim communities. Slight notes that Islamic scholar David Margoliouth in 1912 referred to Britain as “the greatest Moslem power in the world,” but it is unclear how influential this idea was, or why the British Empire's role as ruler of the majority of the world's Muslims at that time has been overlooked by scholars until now.

Slight's book raises a number of interesting questions about Islam and European empires that other scholars will hopefully take up. One is how the Muslim empire he describes corresponded to the racialized construction of the “Muslim world” that also took shape within the context of global empire in the late 19th century, as Cemil Aydin recently argued. Slight describes Britain's Muslim empire as a site of Anglo–Muslim interactions and (in the case of hajj administration in Bombay) cooperation and mutual dependence. But to what extent was this imagined Muslim empire that suddenly cohered in the minds of British officials also informed by increasingly racialized understandings of Muslims and their “civilization” as separate from and inferior to Europe? And what role did Muslim elites—who embraced the European idea of the Muslim world for their own purposes, to advance the idea of Islamic civilization as foundational to the rise of the West—play in the elaboration of the idea of Britain's Muslim empire?

Slight notes that British involvement in the hajj was necessarily of the greatest scope and scale of all empires—given that its empire was the largest and included more Muslims than any other—but this idea deserves some scrutiny. In the 19th century, the hajj became a mass phenomenon and Muslims made the long-distance journey through various colonial possessions and empires. Russia suddenly became a crossroads of hajj traffic, due to its railroad and steamship networks, and drew many non-Russian subjects into and through its lands to access these new routes to Mecca. And in the hajj hub of Jeddah, Russian, British, and Ottoman officials quarreled over who had the legal rights to “protect” hajj pilgrims from lands not formally colonized by Europeans (Afghan, Bukharan, and Qing Muslims mainly), as part of imperial rivalries in Ottoman and Central Asian domains. Colonial hajj support was a mixed, overlapping, and messy project, and, as Slight notes, European involvement in the pilgrimage was not contained within the artificial borders of individual empires.

Along these lines, the map of “Major Hajj Routes in the Age of Empire” nicely details land and sea routes from Africa to Asia, but it leaves out railroad routes through Russian-ruled lands (including the Caucasus and Central Asia) that were also integral to the new network of modern global hajj routes forged in the colonial era. These railroad routes served not only Russian-subject hajj pilgrims, but also those from Persian, Qing, and Afghan lands. Given Slight's important points that the hajj entangled European powers with one another in new ways, and that studying it demands that we “see beyond the artificial borders drawn by European empires” (p. 8), this map regrettably equates 19th-century empire with the British Empire.

Slight's book joins a growing number of histories of Dutch, French, and Russian colonial involvement in the hajj. Departing from previous studies that cite defensive reasons for European involvement in the hajj (following William Roff's “sanitation and security” thesis), Slight argues that British involvement was ultimately and unsuccessfully an attempt to “gain legitimacy among its Muslim subjects” (p. 5). In this sense, Britain acted “like a Muslim power,” much like the Ottoman, Safavid, and Mughal empires that had also sponsored Islamic practices such as the hajj to bolster their legitimacy, a comparison that Slight urges us to consider.

This book is strongly recommended for courses on British imperial history, comparative empires, global history, and Islamic history.