John McHugo's A Concise History of Sunnis & Shiʿis surveys the historical development of Sunni and Shiʿi identities from the 7th-century lifetime of the Prophet Muhammad to the present, approximately 2013, providing students and non-specialists with one clear account of the development of Muslim sectarian identities. McHugo presents an important argument that bears repeating in a book aimed at a general audience: for the majority of history, Sunni and Shiʿa have lived in harmony and the violence associated with contemporary sectarianism in the Middle East has not been a permanent feature of Sunni–Shiʿi relations. Rather, McHugo outlines the origins and development of the division between different religious groups within Islam, providing an in-depth account of the diversity within medieval Islamic identities and how these identities have become politicized in the modern era.

The scope of A Concise History of Sunnis and Shiʿis is impressive. It is divided into two parts: Part 1 consists of seven chapters examining early Islamic history through the Ottomans, Safavids, and Mughals, while Part 2 analyzes the long 19th century into the 21st century in six additional chapters. However, simply stating the range of the book does not do it justice: McHugo manages to deal effectively with not only the broad extent of Muslim history but also incorporates the complexity of divergent perspectives on early Islamic history. For example, the story of the Sunni–Shiʿi split remains contested. Rather than simply present a finished narrative as a fait accompli, McHugo shows some of the competing views of the events after the death of the Prophet Muhammad. Providing his readers with this diversity of narratives allows them to understand the complexity of early Islamic history and may, perhaps, give them insight into understanding how the first Muslims came to civil war over the question of who should lead their community. In addition to the narrative of early Islamic history, he also brings in topics as varied as the emergence of the Druze, Gnostic sects of Islam, the effect of the Mongols and Turkic tribes on the development of Islam, the Safavids and their influence on Shiʿism in Iran, and the split between the Akhbaris and Usulis.

McHugo's account is strongest in its coverage of modern sectarian history. Building upon recent scholarship, such as Sectarianization: Mapping the New Politics of the Middle East (Oxford: Oxford University Press, 2017) edited by Nader Hashemi and Danny Postel, McHugo traces the increasing sectarianization of the Sunni–Shiʿi relationship to the era following the Iranian Revolution in 1979 through the U.S. invasions of Afghanistan (2001) and Iraq (2003). His chapter “Tides Ebb and Flow,” which covers the exceedingly complex period between World War II and 1979, manages to address the effects of Arabism, nationalism, the discovery of oil and concomitant rise of Saudi power, as well as debates within Iran between anti clerical Marxists and the religious establishment. In the final chapter, “Wedges into Fault Lines,” McHugo provides an incredibly clear and concise account of how the fall of Saddam Hussein led to the breakdown of Iraqi society into violent sectarian factions, which led to a regional increase in sectarianization. He contextualizes this process within the competition between Shiʿi Iran and Sunni Saudi Arabia, showing how the failure of the Arab Spring protests was sectarianized, weaponized, and turned into a proxy war.

For the period spanning the 10th through 14th centuries, however, I fear that McHugo may sometimes leave a student audience needing more background. The complexities of this era can be difficult to present to even a more advanced reader, especially in a “concise” history, but McHugo's chapter “Of Ismailis, Assassins, Druze, Zaydis, Gnostic Shiʿis, Alawis and Sufis” addresses a few too many movements in medieval Islamic sectarianism for a more general reader to follow easily. It very quickly becomes overly encyclopedic. Further, this chapter, in particular, overly relies on more general works on Shiʿism by Heinz Halm and Moojan Momen. While no one can challenge the erudition of their contributions to our understanding of Islamic history, I was surprised that McHugo did not cite or include references to a broader range of authors and works on medieval Islamic sectarianism. For example, he cites an article by Farhad Daftary in The New Cambridge History of Islam (New York: Cambridge University Press, 2010) but none of Daftary's other more in-depth work on Ismaʿilism. I was particularly surprised not to see any citations of Najam Haider's excellent recent work on Shiʿism.

However, while I would have liked McHugo to spend a few more pages on medieval sectarianism, I suspect that the purpose of his book lies with providing students with an overview to grapple with the issues of contemporary Islamic sectarianism. In this task, McHugo overwhelmingly succeeds. It is clearly written in accessible language and McHugo provides a thorough index and glossary of terms. I would not hesitate to recommend this book or assign it to an advanced class of undergraduates.