In just over a century the face of Christianity has changed dramatically. Some estimates place the number of Pentecostals around the world at nearly 500 million. The majority of these Christians live in the global south. The rapid growth of Pentecostalism amidst vastly diverse cultures and all economic classes is nothing short of astonishing: ‘Within the past thirty years there has been an estimated 700 per cent increase in the number of Pentecostal believers, who represent about a quarter of the world's Christian population and two-thirds of all Protestants’ (p. 2). Pentecostal churches range from small groups of believers meeting in the homes of uneducated pastors to mega-churches claiming hundreds of thousands of active members, organised by savvy ‘CEO-style’ spiritual leaders.

Studying global Pentecostalism is a reliable guide to current issues, theories and methods in Pentecostal studies. This important collection explores the relatively short history of scholarship on Pentecostalism through fourteen critical essays from distinct disciplinary perspectives. Specialists in history, sociology, psychology, anthropology and theology each contribute to this remarkably unified volume. To my surprise, not a single essay is written by either an individual from the global south or one who is currently living in the majority world (that is, teaching outside of Europe and North America), although several essayists draw from extensive fieldwork in Africa and Latin America. A constant refrain among the authors is the emergence of a critical methodology that rejects earlier trends towards hagiography and polemics.

Although the editors have organised the essays in three parts – ‘Interdisciplinary perspectives’; ‘Social sciences and humanities’; and ‘Theology’ – there is overlap throughout. Allan Anderson's opening essay, ‘Varieties, taxonomies, and definitions’, unravels disciplinary assumptions and proves especially helpful for delineating the complexity of the field. Anderson distinguishes between four primary approaches (i–iv) to the study of Pentecostalism. The ‘typological’ approach (i) differentiates between four related types of Pentecostals, each with its own set of subtypes: classical Pentecostals (most frequently linked to the Azusa Street revival), older independent and Spirit churches (often associated with China, India and subSaharan Africa), older charismatic churches (including historic mainline denominations such as charismatic Anglicans), and neo-Pentecostal and neo-Charismatic Churches (churches influenced by faith evangelists such as Oral Roberts and so-called Third Wave churches, for example). While early ‘social scientific’ approaches (ii) tended to emphasise aberrant behaviours among Pentecostals, recent studies underscore the nimble social and cultural patterns, exemplified by a highly flexible use of technology and modern communication systems. ‘Historical’ approaches (iii) typically locate the origin of Pentecostalism at the Azusa Street Revival in Los Angeles (1906), but critiques of western historiography and provincial archival sources have called widespread historical assumptions into question: ‘the Welsh revival (1904–5) and Pandita Ramabai's Mukti Mission revival in India (1905–7)’, among other movements before and around the time of Azusa, must also be taken into consideration as part of a broadly ‘polycentric approach’ to the historical origins of Pentecostalism (p. 25). Lastly, the ‘theological’ approach (iv) relies on essentialist expressions of belief that appear to transcend local context, especially the predominant emphasis on Acts ii-styled claims about Holy Spirit ‘baptism’ or ‘infilling’. Anderson's opening essay thereby elucidates a pivotal, overarching theme of the book: ‘It is probably more correct to speak of Pentecostalisms in the contemporary global context’ (p. 15; cf. Robeck, p. 290).

As several authors note, Pentecostalism is difficult to define. Multiple essays reveal how notions of ‘essential’ characteristics – whether based on culture, gender, race or narrative – provide key indicators of Pentecostal identity, but inevitably require a fully interdisciplinary approach. Even in part ii, where a series of essays written from different research perspectives are grouped together (psychology, anthropology, sociology and history are each represented), the need for interdisciplinary research is apparent. I was fascinated by the chapter on ‘Psychology of religion’ (ch. vii), since the authors brought theology and empirical research into a common conversation. While early studies of glossolalia frequently linked Pentecostal experiences to ‘psychodynamic concepts such as schizophrenia, hysteria, and regression’, recent research takes better account of neuroimaging studies of brain activity as well as both quantitative and qualitative research on human religiosity (p. 151). Christian theology certainly has its place in this volume, too, but the formal representatives (including essays by Veli-Matti Kärkkäinen, Amos Yong and Tony Richie, Mark Cartledge and Cecil Robeck) are postponed to the final section. Trinitarian theology, ecclesiology, missions and spirituality are all reflected in recent Pentecostal scholarship, but several topics may surprise newcomers: inclusivist notions of salvation, Pentecostal theologies of religion and a decades-long commitment to ecumenism.

The problems of particularity and universality are especially acute for historians. As Michael Bergunder explains in ‘The cultural turn’ (ch. iii), Pentecostal Christians worldwide claim unique spiritual revivals in Korea, India, Chile and the United States during the first decade of the twentieth century. These simultaneous movements indicate that Pentecostalism resists linear description. Pentecostalism commences not in any single revival (such as Azusa Street) or a peculiar manifestation (such as speaking in tongues), but in the subsequent formation of a ‘distinct global synchronous Pentecostal network’ in later years (p. 63). Outliers remain difficult to classify, too. African Independent Churches, which share some theological, liturgical and even historical relationships with classical Pentecostals, resist easy categorisation (pp. 64–8). Similarly, Cornelis van der Laan's essay on ‘Historical approaches’ (ch. x) explains that shifts in historiography have led to significant reevaluations among scholars as well. Pentecostal historians have employed a range of interpretive approaches, from providential descriptions of divine renewal to functional descriptions of Pentecostal spirituality amid poverty and powerlessness (pp. 208–9). Moreover, the voices of Asian, African and Latin American Pentecostals ‘from below’ have gradually replaced the long-standing preference for white, western men in historical narratives.

Studying global Pentecostalism goes a long way towards dispelling myths about Pentecostal spirituality, revealing strong social and material aspects of the movement that are too often overlooked in favor of arid and dated assessments of a fluid network still very much in flux. Newcomers to the field will benefit from a thorough review of this in-depth, scholarly study. Historians are essential participants in the interdisciplinary recovery of local Pentecostal narratives, but significant questions remain unanswered: can historians continue to speak of global, Pentecostal coherence? Will further research expose Pentecostalism as nothing more than innumerable, fractured sects? Do archival sources confirm the presence of broad, unifying networks built on common practices or shared beliefs? Finally, will the emerging critical spirit among Pentecostal academics, the openness to new and imaginative theological paradigms, and the gradual assessment of Pentecostal spirituality from outsiders indicate an ever-widening gap between Pentecostal laity and professionals? One thing is certain: Pentecostalisms seem destined to multiply.