This book is about the boisterous beginnings of the American pentecostal movement and the ideas that defined it during its formative years. It focuses on the movement's most articulate spokespersons and how those twelve individuals rethought the Christian faith in light of their new experience of God and developed a new pentecostal language of faith. As the pentecostal movement has grown, the ideas of these early theologians have been borrowed, appropriated, extended, and refined in ways they did not foresee or fully intend. Yet the basic framework has remained the same. Jacobsen examines these migrating ideas in their original forms of expression, and he explores how these inventive thinkers improvised language, bent the meanings of old words, and invented new phrases to help their readers better understand the ways they believed God's Spirit was present in the world.