This book is put forward with much diffidence, for I am well aware of its insufficiencies. My original idea was to produce a work covering all the principles of painting, but after many years spent in considering the various recorded theories relating to Æsthetic problems, and in gathering materials to indicate how the accepted principles have been applied, I came to the conclusion that a single life is scarcely long enough for the preparation of an exhaustive treatise on the subject. Nevertheless, I planned a work of much wider scope than the one now presented, but various circumstances, and principally the hindrance to research caused by the war, impelled me to curtail my ambition. Time was fading, and my purpose seemed to be growing very old. I felt that if one has something to say, it is better to say it incompletely than to run the risk of compulsory silence. The book will be found little more than a skeleton, and some of its sections, notably those dealing with illusions in the art, contain only a few suggestions and instances, but perhaps enough is said to induce a measure of further inquiry into the subject.

That part of the work dealing with the fine arts generally is the result of long consideration of the apparent contradictions involved in the numerous suggested standards of art. In a little book on The Position of Landscape in Art (published under a nom de plume a few years ago), I threw out, as a ballon d'essai, an idea of the proposition now elaborated as the Law of General Assent, and I have been encouraged to affirm this proposition more strongly by the fact that its validity was not questioned in any of the published criticism of the former work; nor do I find reason to vary it after years of additional deliberation. I have not before dealt with the other propositions now put forward.

The notes being voluminous I have relegated them to the end of the book, leaving the feet of the text pages for references only.

Where foreign works quoted have been translated into English, the English titles are recorded, and foreign quotations are given in English, save in one or two minor instances where the sense could not be precisely rendered in translation.

E. G.

New York, January, 1919.