In ordinary times a paper on Recent Activities of Catholic Historians could have meant nothing more than a bibliographical survey or a critical enumeration of the writings of Catholic authors on the subject of ecclesiastical history during the preceding year or even the preceding six months. Such an approach to the matter is now impossible. The last four years have been lean years in historical bibliography. Historians may not have been idle; but they have concerned themselves more with the problems of the present than with the problems of the past. The output of historical works has been meager. Our knowledge of them is more meager still. We have not only been shut off, through the exigencies of war, from a large part of the world, but we have been deprived of the guidance of historical periodicals which would make it possible to give a complete survey of the actual conditions of historical writing and investigation at the present. Many of these periodicals have gone out of existence, others have been temporarily suspended, and many more have been inaccessible because of censorship regulations, while others have changed their character to such a degree that they hardly deserve the name of historical magazines.