Ir was my original intention that the following treatise should be included in the third part of my History of Early Christian Literature. However, it grew under my hands to such an extent that I now publish it in a separate volume. It must form the first of a few other treatises on the subject of Introduction to the New Testament which will appear shortly, for some of the cardinal problems of this branch of Biblical study are still far from being set in so clear a light as to permit of their being dismissed in a short essay.