Passing by much that is of the highest importance, [the author] has attempted to point out the main movements of Christian thought from the close of the Apostolic Age to the dawn of the Reformation. . . . The writer believes firmly in the evolutionary standpoint as alone explanatory of the history of the Christian Church as the expression of the will of the Holy Spirit. He admits, therefore, the principle of development as not only an historic fact, but as part of the work of God. True Christianity is not to be found by going back to some ill-defined period of antiquity, the beliefs and practices of which it is now almost impossible to reconstruct, but by the incorporation into itself of the ever-enlarging knowledge, the ever-expanding horizons of life. It is the glory of Christianity that this can be done. --from the Preface