This work traces the importance of gospel hymnody in shaping popular theology and influencing American culture. In particular, it analyzes how gospel hymns were created, defined, and performed, how they helped produce interdenominational cooperation among conservative evangelicals during the early the early twentieth century, and how they became part of larger American culture. In worship services, mass revival meetings, and home gatherings, music was a central feature. Increasingly though, the music used in these contexts was standardized and became a point of connection between disparate Protestant groups. This was largely achieved through the mass marketing of gospel hymns in the publications and broadcasts controlled by interdenominational institutions, such as the Moody Bible Institute. Through these channels, gospel hymnody became a point for interdenominational cooperation among conservative evangelicals. Understanding how gospel hymns were being utilized by the interdenominational evangelicals also helps delineate the parameters of evangelical culture and its relationship to broader American culture. In various evangelical denominations, debates over gospel hymns both inside and outside the church building provided a means for negotiating theological, social, and cultural boundaries. Through creating, defining, and performing music in specific ways, evangelicals placed themselves within the mainstream of American middle class culture and distinct from both an emerging separatist fundamentalism and an increasingly secular liberalism.