It may seem extraordinary that the issue of heresy has been largely overlooked or marginalized in the history of the Reformation in the German-speaking lands. Apart from specialized studies, mostly dealing with the attitude of the established Reformers to radicals and sectaries on their flanks, there has been no specific treatment of what was perceived as heresy, who the heretics were, and how heresy was to be combated. In an oecumenical age the issue of heresy, which by definition requires the identification of those who placed themselves beyond the pale of the Christian community, is deeply embarrassing: it surely belongs to an earlier age in which apologetics and dogmatics dominated religious discourse.