Pentecostalism is arguably the most vibrant and rapidly growing religious movement of the 20th century, circling the globe in less than 25 years. Characterized by speaking in tongues, miracles, television evangelism, and megachurches, it is also known for its small-group meetings, empowerment of individuals, liberation of women, and humanitarian concerns. In this Very Short Introduction, William K. Kay outlines the origins and growth of Pentecostalism,...