Pentecostalism is one of the fastest-growing religious movements in the world. Groups in the United States dominated early Pentecostal histories, but recent global manifestations have expanded and complicated the definition of Pentecostalism. This volume provides a nuanced overview of Pentecostalism's various manifestations and explores what it means to be Pentecostal from the perspectives of both insiders and outsiders. Leading scholars in the field use a multidisciplinary approach to analyze the historical, economic, political, anthropological, sociological and theological aspects of the movement. They address controversies, such as the Oneness-Trinity controversy; introduce new theories; and chart trajectories for future research. The Cambridge Companion to Pentecostalism will enable beginners to familiarize themselves with the important issues and debates surrounding the global movement, while also offering experienced scholars a valuable handbook for reference.