This book represents the result of further reflections on moral theory, since I published in 1930 a book called The Right and the Good. I have tried, in the present book, to take account of such books and articles later than 1930 as have come my way and as seem to have a close relation, whether in the way of agreement or in the way of criticism, to the views expressed in the earlier book. The result of further reflection has been to confirm me in most of the views I earlier expressed, but by no means in all. Some of the topics considered have already been much discussed by other writers; the issues have been much clarified in the course of the discussion, and in such cases I feel comparatively confident that the views I have argued for are true, or near the truth. Other topics (especially some discussed in Chapter XI) have not been much discussed before; there have been few sign-posts saying 'This way to the truth', 'Proceed at your own risk', or 'No road this way'; and in these cases I put forward my conclusions very tentatively, in the hope that discussion of them may tend to clear up the issues.