This volume tells the story of a mid-nineteenth-century theological movement emanating from the small German Reformed Seminary in Mercersburg, Pennsylvania, where John Williamson Nevin and Philip Schaff taught. There they explored themes—such as the centrality of the incarnation for theology, the importance of the church as the body of Christ and the sphere of salvation, liturgical and sacramental worship, and the organic historical development of the church and its doctrines—that continue to resonate today with many who seek a deeper and more historically informed expression of the Christian faith that is both evangelical and catholic.