Our interest in Luther's struggle for faith is not merely historical. We do not investigate this subject as we do Luther's views on monstrosities or the names for the gems in the Apocalypse, nor do we probe into his spiritual trials in order to collect additional specimens of abnormal psychology. If he was abnormal then the abnormal has become the normal. All of us today are engaged in a struggle for faith and our concern is not so much with the disease as with the cure. How was it that Luther, despite his travailing of spirit, could be so tremendous in his faith, so incredible in his courage, so astounding in his output? Luther's faith is our quest.

Since the close of World War I the study of Calvin has been advanced by the labors of many scholars. This article presents a classified bibliography of what in the writer's judgment are the materials of chief importance in this enlarging field of research. A similar treatment of the historical literature concerned with the Reformed churches of Europe to the opening of the Thirty Years' War is in preparation.