Among modern philosophers I have been especially occupied with, and variously stimulated or warned by, Spinoza, with his deep religious intuition and aspiration, and his determinist system, so destructive because taken by him as ultimate; Leibniz, with his admirably continuous sense of the multiplicity in every living unity, of the organic character, the _inside_ of everything that fully exists, and of the depth and range of our subconscious mental and emotional life; Kant, with his keen criticisms and searching analyses, his profound ethical instincts, and his curious want of the specifically religious sense and insight; Schopenhauer, with his remarkable recognition of the truth and greatness of the Ascetic element and ideal; Trendelenburg, with his continuous requirement of an operative knowledge of the chief stages which any principle or category has passed through in human history, if we would judge this principle with any fruit; Kierkegaard, that certainly one-sided, yet impressively tenacious re-discoverer and proclaimer of the poignant sense of the Transcendent essential to all deep religion, and especially to Christianity, religion’s flower and crown; and Fechner, in his little-known book, so delightfully convincing in its rich simplicity, _die drei Motive und Gründe des Glaubens_, 1863. Of quite recent or still living writers, two have been used by me on a scale which would be unpardonable, had the matters treated by them been the direct subjects of my book. In Part First whole pages of mine are marked by me as little but a _précis_ of passages in Dr. Eduard Zeller’s standard _Philosophy of the Greeks_. I have myself much studied Heracleitus, Parmenides, Plato and Plotinus; and I have, also in the case of the other philosophers, always followed up and tested such passages of Zeller as I have here transcribed. But I did not, for by far the most part, think it worth while, on these largely quite general and practically uncontested matters, to construct fresh appreciations of my own, rather than to reproduce, with due consideration and acknowledgments, the conclusions of such an accepted authority. And already in Part First, but especially in Part Third, I have utilized as largely, although here with still more of personal knowledge and of careful re-examination, considerable sections of Professor H. J. Holtzmann’s _Lehrbuch der Neutestamentlichen Theologie_, 1897--sections which happen to be, upon the whole, the deepest and most solid in that great but often daring work. The same Professor Holtzmann is, besides, a most suggestive religious philosopher; and his penetrating though very difficult book _Richard Rothe’s Speculatives System_, 1899, has also been of considerable use.