This study is limited to the formative phase of the Pentecostal movement from the late nineteenth century to the early 1930s. The Depression years were years of phenomenal growth for the Pentecostals, but by then the movement had entered a different stage of development; much of the spontaneous element had become ritualized and what had been a fluid movement had largely crystallized into a number of denominations. While my primary focus has been on Pentecostalism as a social movement, I have been ever mindful of the interaction between theological and sociological influences, between ideas and action. - Introduction.