EDITORS PREFACE TO THE FIRST EDITION: THE works by which Professor Green has hitherto been chiefly known to the general public are his Introduction to Messrs. Longmans edition of Humes Philosophical Works, and his articles in the Contemporary Review on some doctrines of Mr. Spencer and Mr. Lewes. When in the year 1877 Mr. Green became Whytes Professor of Moral Philosophy, his main desire was, both in his teaching and writing, to develope more fully and in a more constructive way the ideas which underlay his previous critical writings and appeared in them. The present trea tise is the first outcome of that desire and doubtless it would have been only the first but for the premature and unexpected death of the author in March, 1882. Even the Prolegomena to Ethics the title is the authors own was left unfinished. The greater part of the book had been used, some of it twice over, in the Professorial lectures and about a quarter of it the first 116 pages was printed in the numbers of Mind f