A spiritual revolution is transforming the religious landscape of Latin America. Evangelical Protestantism, particularly Pentecostalism, has replaced Catholicism as the leading religion in thousands of barrios on the urban periphery. But in few Latin American nations have Protestants multiplied as rapidly as in Brazil. What accounts for this rise? Combining historical, political, and ethnographic research, R. Andrew Chestnut shows that the relationship between faith healing and illness in the conversion process is integral to the popularity of Pentecostalism among Brazil's poor. He augments his analysis of the economic and political factors with extensive interview material to capture his informants' conversion experience. In doing so, he presents both a historical framework for a broad understanding of Pentecostalism in Latin America and insight into the personal motivations and beliefs of the crentes themselves.