Gunther Gassmann is former Director of the Commission on Faith and Order at the World Council of Churches, Geneva, Switzerland, and Distinguished Visiting Professor at the Lutheran Theological Seminary, Gettysburg, Pennsylvania. Scott H. Hendrix is Professor Emeritus of Reformation History and Theology at Princeton Theological Seminary. He earned a PhD in Reformation studies from Tubingen University in Germany, and has chaired the Continuation Committee of the International Congress for Luther Research. Among his many publications are Luther (2009) and Martin Luther: A Very Short Introduction (2010).

