Broadcasting the Faith tells the riveting story of the American church's embrace of radio in the early decades of the twentieth century. By investigating major radio personalities like Walter Maier, Aimee Semple McPherson, Harry Emerson Fosdick, and Charles Fuller, this study considers the implications for theology in America when Christianity moved to the airwaves. In the heyday of radio, religious-radio preachers sought to use their programs to counter the secularization of American culture. Ultimately, however, their programs contributed to secularization by accelerating changes already evident in both the conservative and liberal streams of American Christianity. To reach a vast American audience, radio preachers transformed their sectarian messages into a religion more suitable to the masses, thereby altering the very religion it aimed to preserve. To make religion accessible to large and diverse audiences, radio preachers accommodated their messages in ways suited to the medium of radio. Although religious-radio preachers set forth to advance the influence of religion in American society, their choice to limit theological substance ironically promoted the secularization of the American church.