Najam Haider's recent survey of Shiite history endeavours to present Shiism as only partially constituted by the majority Twelver sect. This stands in contrast to most prominent English-language introductions (notably Moojan Momen's 1987 An Introduction to Shiʿi Islam: The History and Doctrines of Twelver Shiʿism, Hamid Dabashi's 2012 Shiʿism: A Religion of Protest, and even Jaʿfar Sobhani's 2001 Doctrines of Shiʿi Islam: A Compendium of Imami Beliefs and Practices), which focus primarily on Twelverism. Haider devotes roughly equal treatment to the three most prominent strands of what might be termed “mainstream” Shiism: Zaydism, Ismailism, and Twelverism. As Haider notes at the outset, this volume need not be read cover-to-cover; depending on one's interest level one could treat it as a reference work – the comparative tables are especially clear and succinct summaries of the text's body. He suggests many ways in which the book or individual chapters can be read as stand-alone units or in conjunction with other specific chapters. The prose is readable even if lacking the thick description of the [Twelver] Shia ethos found in, for example, the relevant chapters of Reza Aslan's 2005 No God but God. Haider's volume will be informative for people ranging from novices in Islamic studies to students and professors of Shiism.

Haider structures Shīʿī Islam in a very accessible way. It consists of four sections, the first two of which encapsulate “Shīʿism” as a single entity and the last two examining the three mainstream branches as discrete movements. Section I posits two poles upon which Shiism as a whole rests: ʿadl (rational divine justice), and the concept of the Imām. While the first pole can certainly be disputed (perhaps the person and cosmological status of ʿAlī is sufficiently distinct from the Imāmate to warrant a seat at the table of foundational concepts), this section certainly gives the reader a meta-context for understanding Shia history. Section II gives the traditional Shiite “community's understanding of” how it initially splintered from the proto-Sunni tradition and then itself divided into splinter groups, usually revolving around the question of succession to the Imāmate more than theological or jurisprudential issues. In Section III, Haider provides one chapter each about the formative events and issues which gave rise and sustenance to each of the three “major” sects, giving roughly equal space to the Zaydis, Ismailis and Twelvers. Section IV parallels its antecedent, describing the later developments and current state of each denomination. Both the timing of the book's publication and the constraints of space preclude treatment of several issues germane to contemporary Shiism. Nothing of the recent or current developments within Mustāʿlī Ismailsm (including the current succession crisis surrounding the group's recently deceased dāʿī) or the forthcoming challenge of determining the next (fiftieth) Nizārī Imām is mentioned. The book is unable, for obvious reasons, to give a retrospective interpretation of ʿAlī Khāmeneī's tenure as Iran's Supreme Leader (he is not mentioned at all), and was written before the Zaydi Houthi takeover of the Yemeni government. A second edition will hopefully include these contemporary geopolitical developments.

The book's greatest strength is paradoxically also its greatest shortcoming. It is distinct in its representation of the diversity within Shiism, yet it is not sufficiently broad to give adequate attention to extant so-called ghulāt (extremist) branches of the Shii tradition (ironic considering the space the author devotes to defunct ones) or even to some of Shiism's more mainstream instantiations. A constant refrain is: “space does not permit discussion of…”. One wonders whether replacing that caveat with a few paragraphs about the Bektaşis, Alevis/Qizilbash, and Nuṣayris/ʿAlawites (and even historical offshoots like the Druzes and Bahais) would advance Haider's project of presenting Shiism in its full diversity. Though he writes these groups off as “smaller communities of localized Shia”, there may be 25,000,000 Alevis and 4,000,000 Nuṣayris in the broader Shia world. A further twenty pages of text would do more good in rounding out the scope than the potential harm in making the book unwieldy. Haider presents the Twelvers, [Nizārī] Ismailis, and Zaydis meticulously, often zooming in historically on formative people and events. An author always has to balance breadth with depth, but when Haider provides the latter it does not always help him paint a picture and therefore draw the reader in. Certainly Shīʿī Islam hits the high points of the history of the three sub-traditions, but they are often presented dryly and thus restrict the readership to those hungry for the facts of Shiism rather than those more interested in its ethos. Shiites are people marked by experience as much as doctrine and arguments over the rightful Imām, and it is this existential dimension which resounds most faintly in this meticulously researched text.

Admirably, Haider devotes his four sections to dispelling a common conflation. Casual observers tend to equate Islam as a whole with either the Sunni or the Arab world, a great disservice to the tradition's rich diversity. Similarly, when talking about Shiites, specialists and non-specialists alike (including some of the above-mentioned introductory surveys) tend to conflate “Shiism” with its largest branch. Notwithstanding the fact that Twelvers might constitute only a slight majority, the assumption that “Shiite” and even “Imāmī” are synonymous with the Twelver tradition strips Shiism of its dynamism (as does a conflation of “Mustāʿlism” with its majority Ṭayyibī sect in the Ismaili world). Haider spends the body of the text dispelling this oversimplification, but at the very end he falls into the trap which he has worked so hard to disarm. In the conclusion he verges on reducing Shiism to Twelverism. This, along with the slight-to-absent mention of fringe sects, dampens the book's major contribution to the field, i.e. its intentional focus on Shiism's diversity. Students of Islam wanting to learn about these less normative strands will need to supplement Haider's laudably broad survey with studies of downplayed contemporary Shia groups. Inclusivism, it seems, always begets exclusivism, even if for purely practical reasons. Still, this is perhaps the most accessible and comprehensive English-language introduction to Shiism available to date.