In this Apologetics volume, The Two Realms and the Separation of Church and State, Joel Biermann explores the Christian teaching of the two realms—church and state—and the way the relationship between them is shifting in American society. The “doctrine” of the separation of church and state is a product of the Enlightenment, post-dating Luther’s distinction of two kingdoms by many generations. The separation of church and state suggests that church and government (state) occupy two independent spheres, between which there should be no interaction, hypothetically preserving both from corruption. Luther’s doctrine of two kingdoms instead suggests just one King—God—who rules in two different ways: by the Gospel (church) and by the “sword” (state). In the present era of uncertainty and confusion regarding the proper relationship of the church and the Christian to the government, the confusion of these two approaches leads to errors and uncertainties about the status and proper voice of the Christian as a citizen. Rev. Dr. Biermann not only distinguishes these two teachings but also articulates faithful Christian citizenship as informed by Lutheran theology.