Sebastian Franck is generally counted among the members of the radical Reformation, which includes a wide range of religious dissenters of the sixteenth and seventeenth centuries who believed that Martin Luther, Huldrych Zwingli, and John Calvin had stopped short of a thorough reform of the church. The group embraced such disparate figures as the Anabaptist Menno Simons, the social reformer Thomas Müntzer, the anti-Trinitarian Michael Servetus, and Franck, who inveighed against all outward manifestations of religion and insisted on the purely spiritual, invisible nature of God, Gods Word, and the Church. Perhaps in no other early modern European does one find the consequences of the spiritualist position so clearly and drastically expressed and lived out as in Franck.

True to his convictions, Franck founded no sect and cultivated no following. His views have been preserved through his writings, most of which Franck, an ardent supporter of...