In the present article, which continues the critical studies of the literature on Church History, published in this Review in 1921–1925, I cannot attempt to cover so wide a field as before, both because of my own advancing years and because, with the enormous yearly increase in the material, no single scholar is any longer in a position to treat it with adequate knowledge. I shall, therefore, limit myself to the field of patristic literature, the subject in which I won my spurs almost half a century ago and with which I have never ceased to occupy myself. Now that the literature of the countries formerly at war with Germany is again accessible to me, the survey can, as in old times, be international. In all these countries, especially in France and Belgium, the investigation of early Christian literature has in recent years had a powerful development, and Germany, under present economic conditions, in spite of unrelaxed industry, is in danger of falling into the rear.