The Reformer had lectured on this Epistle of St. Paul's in 1519 and again in 1523. It was his favorite among all the Biblical books. In his table talks the saying is recorded: "The Epistle to the Galatians is my epistle. To it I am as it were in wedlock. It is my Katherine." Much later when a friend of his was preparing an edition of all his Latin works, he remarked to his home circle: "If I had my way about it they would republish only those of my books which have doctrine. My Galatians, for instance." The lectures which are preserved in the works herewith submitted to the American public were delivered in 1531. They were taken down by George Roerer, who held something of a deanship at Wittenberg University and who was one of Luther's aids in the translation of the Bible. Roerer took down Luther's lectures and this manuscript has been preserved to the present day, in a copy which contains also additions by Veit Dietrich and by Cruciger, friends of Roerer's, who with him attended Luther's lectures. In other words, these three men took down the lectures which Luther addressed to his students in the course of Galatians, and Roerer prepared the manuscript for the printer. A German translation by Justus Menius appeared in the Wittenberg Edition of Luther's writings, published in 1539. The importance of this Commentary on Galatians for the history of Protestantism is very great. It presents like no other of Luther's writings the central thought of Christianity, the justification of the sinner for the sake of Christ's merits alone. (From the Preface)