This introductory chapters provides a broad overview of the historic development, diffusion, and study of evangelical Christianity in Latin America from the nineteenth century to the present. It situates the movement’s tremendous growth within longer trajectories of migration, missionary activity, and local religious change. It also outlines the emergence of Latin American evangelicalism as a field of academic inquiry, tracing shifting paradigms from sociological and political analyses to more recent turns to cultural, intellectual, and ethnographic approaches. In doing so, it underscores the deeply intertwined nature of faith, politics, and social transformation across the shifting terrain of global networks and local innovations that defined the experiences of the region’s earliest evangelicals. To conclude, it offers a blueprint of the book—including primary sources and analyses from scholars within the region—to foreground the voices of early believers and document the movement’s transformation into a permanent feature of Latin America’s religious, political, and social landscape.