At the present time in every Christian country a corps of well-trained scholars are devoting their lives to nearly every phase of Church history, and the outlook is most gratifying. The literature on Church history, taken as a whole, is perhaps more voluminous than that on any other phase of history. The use of the sources is, in consequence, at the very outset a problem of selection. It is apparent, therefore, that the following brief lists are not meant to be exhaustive. Only the most valuable collections of original documents, and also the most reliable books of a secondary character are included. Special care has been taken to mention all useful collections of sources in the English language. At the conclusion of each chapter will be found references to the sources on special topics. THE MOST IMPORTANT COLLECTIONS OF PRIMARY SOURCES ARE: A.--Official Documents: I.--In English: 1.--Brett, T., _Collection of the Principal Liturgies_. Lond., 1838. 2.--Fulton, J., _Index Canonum_. N. Y., 1892. 3.--Gee, H., and Hardy, W. J., _Documents Illustrative of English Church History_. N. Y., 1896. 4.--Hammond, C. E., _Liturgies, Eastern and Western_. Lond., 1878. 5.--Henderson, E. F., _Select Historical Documents of the Middle Ages_. Lond. and N. Y., 1892. 6.--Neale, J. M., _The Liturgies of St. Mark, St. James, St. Clement, St. Chrysostom, and St. Basil_. 2 vols. Lond., 1859. 7.--Neale, J. M., and Webb, B., _The Symbolism of Churches and Church Ornaments_. Lond. and N. Y., 1893. 8.--Ogg, F. A., _Source-Book of Mediæval History_. N. Y., 1908. 9.--Palmer, W., _Origines Liturgicæ_. 2 vols. Lond., 1845. 10.--Roberts and Donaldson, _Ante-Nicene Christian Library_. Vol. xxiv. Edinb., 1872. 11.--Robinson, J. H., _Readings in European History_. Vol. i. Boston, 1906. 12.--Schaff, P., _The Creeds of Christendom_. 3 vols. N. Y., 1878. 13.--Swainson, C. A., _The Greek Liturgies_. Lond. and N. Y., 1884. 14.--Thatcher and McNeal, _A Source Book for Mediæval History_. N. Y., 1907. 15.--University of Penn., _Translations and Reprints of Original Sources of European History_. Phil., 1894 to present. 16.--Winer, G. B., _Comparative View of the Doctrines and Confessions of Christendom_. Edinb., 1887. II.--In Foreign Languages: 1.--Councils and Synods: (1).--Binius, S., _Concilia Generalia et Provincialia Græca et Latina_. 4 vols. Best ed., Cologne, 1606. (2).--Labbé, P., _Concilia_. 18 vols. Paris, 1671. Carried by others to 1727. (3).--Hardouin, J., _Conciliorum Collectio_. 12 vols. Paris, 1715.