The Islamic State in Africa is an important analysis of the spread of the Islamic State in Iraq and Syria (ISIS), hereafter IS, outside of Syria and Iraq (2014–19). IS pursued a similar strategy to that of al-Qaeda after its eviction from Afghanistan in that it contacted (or was contacted by) local terrorist groups in parts of the world outside its central theater of operations in the Middle East. The book considers how local insurgent organizations in Africa were integrated into the larger IS network. The authors also conclude that, contrary to what might have been expected, the African provinces (wilayas) of IS did not break away in the wake of the IS defeat in Syria; instead, the defeat provided a means for the larger terrorist network to perpetuate itself via its proxies.

Writing about the inner workings of IS, al-Qaeda, or any current terrorist or insurgent group is challenging, due to lack of access to reliable sources. The four authors of The Islamic State in Africa have compiled a remarkable 126 pages of notes (in a 456-page volume) of open-source material. The inclusion of IS media sources alongside North American and European journalistic and scholarly sources is very useful for a broader understanding of the operations and motives of the wilayas in Africa. James Warner (West Point) and his three colleagues have think-tank and security consultant backgrounds; they are conversant with the vast array of secondary source materials needed to elucidate IS expansion on the African continent.

The book comprises nine case studies of successful and failed IS branches in Africa: Libya, Algeria, Sinai, Tunisia, the West Africa Province (Nigeria, formerly Boko Haram), the West Africa Province—Greater Sahara, the Central Africa Province—Democratic Republic of the Congo and the Central Africa Province—Mozambique. The problem here is to tie these disparate groups together in a single analytical framework.

To do this, the authors develop a central concept: the “bayah”—the local insurgent group’s pledge of allegiance to the Islamic State. Three specific periods are treated in each case study. The first is the pre-bayah period between Abu Bakr al-Baghdadi’s declaration of the ISIS cali-phate in Mosul (June 2014) and the oath of allegiance by the local group. The second is the bayah period from the oath of allegiance to its recognition by IS central authorities, which the authors call “affiliate unity validation” (24). Most of the groups had to prove their operational effectiveness to IS before being officially recognized. The final phase is the post-bayah period, when the local groups became a recognized province of IS up to the death of Baghdadi (27 Oct. 2019). The process described above is integral to the authors’ description of the “democratiza-tion of jihad”: that is,

The competition between al-Qaeda and IS for local affiliates is thus at the center of the argu-ment, but one misses a more systematic analysis of the prior al-Qaeda implantation on the con-tinent for comparative purposes. It remains unclear why the “democratization of jihad” favored IS and not al-Qaeda. Also unclear is the extent to which intervention by outside powers, notably the French operation in Mali that began in 2013, induced various local groups to join IS and/or shift allegiance away from al-Qaeda.

The book’s case studies will be instructive for scholars of IS and al-Qaeda, but also for those concerned with the development of terrorist and insurgent groups in general. The authors clar-ify the origins of each IS affiliate, its leaders, and its activities before joining IS Central. The failed attempt in Algeria is of particular interest. Not all IS affiliates have become fully active or-ganizations, and the authors show the value of examining failures. In Algeria, several high-ranking members of previous al-Qaeda-affiliated organizations broke away to create a separate group—IS in Algeria, or Wilaya Jazair. The authors contend that, rather than benefiting the new IS province, the splintering from al-Qaeda in the Islamic Maghreb (AQIM) destroyed the group:

Thus, IS membership does not always benefit local groups; and, in addition, IS Central did not make any effort to come to the rescue of its Algerian affiliate.

The failed Algerian attempt to become a province of IS is a part of the book’s larger argu-ment about the varying degrees of IS control over its African partners. The authors claim the African affiliates of IS can be seen as “sovereign subordinates” (290). The African groups mostly retained their freedom of action, while enjoying the benefits of IS membership. In short, they were “far more sovereign than subordinate” (294). The extent to which this held true, however, varied by group and time periods. In contrast to the indifference shown to its Algerian prov-ince, IS Central sometimes intervened in the operations and organization of certain African partners elsewhere. A notable example explored at length in the book is the role of IS Central in the downfall of Abubakar Shekau as leader of Boko Haram.

The Islamic State in Africa makes a significant and welcome contribution to the literature on the contemporary organization of terrorist and insurgent groups. It will engage and instruct scholars of terrorism and international security as well as academics working in area studies. Policymakers will value its plethora of useful information and clear overview of the IS approach to the African continent as a whole; this is especially welcome, given that studies of terrorism in Africa have converged more on specific groups and regions. In short, The Islamic State in Africa will provide an essential starting point for future research as more primary sources become available.