The Prolegomena, which have grown to more than twice their original extent, are two-thirds of them new matter. The lapse of twenty years could not but involve a change in the writer's attitude, at least in details, towards both facts and problems. The general purpose of the work, however, still remains the same, to supply an introduction to the study of Hegel, especially his _Logic,_ and to philosophy in general. But, in the work of altering and inserting, I can hardly imagine that I have succeeded in adjusting the additions to the older work with that artful juncture which would simulate the continuity of organic growth. To perform that feat would require a master who surveyed from an imperial outlook the whole system of Hegelianism in its history and meaning; and I at least do not profess such a mastery. Probably therefore a critical review will discern inequalities in the ground, and even discrepancies in the statement, of the several chapters. To remove these strains of inconsistency would in any case have been a work of time and trouble: and, after all, mere differences in depth or breadth of view may have their uses. The writer cannot always compel the reader to understand him, as he himself has not always the same faculty to penetrate and comprehend the problems he deals with. In these arduous paths of research it may well happen that the clearest and truest perceptions are not always those which communicate themselves with fullest persuasion and gift of insight. Schopenhauer has somewhere compared the structure of his philosophical work to the hundred-gated Thebes: so many, he says, are the points of access it offers for the pilgrims after truth to reach its central dogma. So--if one may parallel little things with his adventurous quest--even the less speculative chapters, and the less consecutive discourse, of these Prolegomena may prove helpful to some individual mood or phase of mind. If--as I suspect--the Second Book should elicit the complaint that the reader has been kept wandering too long and too deviously in the _Porches of Philosophy_, I will hope that sometimes in the course of these rovings he may come across a wicket-gate where he can enter, and--which is the main thing--gather truth fresh and fruitful for himself. Fourteen chapters, viz. II, XXIV, and the group from VII to XVIII inclusive, are in this edition almost entirely new. Three chapters of the first edition, numbered XIX, XXII, XXIII, have been dropped. For the rest, Chaps. III-VI in the present correspond to Chaps. II-V in the first edition: Chap. XIX to parts of VII, VIII: Chaps. XX-XXIII to Chaps. IX-XII: Chaps. XXV-XXX to Chaps. XIII-XVIII: and Chaps. XXXI, XXXII to Chaps. XX, XXI. But some of those nominally retained have been largely rewritten.