American Christianity is so diversified and confusing and its material is of such vast extent that the scholars who have worked at the broader aspects of its history have had to bring to their study certain interpretative theses in order to find their way through the material at all. These interpretative theses, some implicitly held and others explicitly stated, some relatively adequate and others fairly weak, have paved the way for a great deal of intensive research, so that the young discipline of American Church History has a solid and illuminating body of material. Out of the research thus far undertaken have sprung new themes of interpretation, so that what may be called an “historiographical cycle” operates. This interaction of research and interpretation has functioned sufficiently well so that the overall picture of American Christian history grows steadily clearer. The process of clarification has, however, proceeded satisfactorily only to a point—to the Civil War. For the years since the Civil War, the picture has not yet come into sharp focus. The interpretative theses thus far proposed have had serious limitations, and as a result the historiographical cycle has not operated to best advantage. The excellent monographic studies that have been done remain therefore somewhat unrelated and leave us with a rather fragmentary understanding of religious history since 1865. Yet in these years occurred decisive developments which must be further probed and clarified if we are to understand more fully the contemporary American religious scene, now so important a part of the total life of the world church. To be sure most of the significant movements of the period have received some attention, but they can be fully understood and their significance grasped only as they are delineated as part of the total history of American Christianity with the interconnections traced and the polarities analyzed. More fruitful and better-directed monographic studies will follow from the setting forth of fresh and rounded themes of interpretation; the historiographical cycle will then operate to better advantage for this important period.