When I originally conceived the idea of the work, of which the first part is now laid before the public in a third and enlarged edition, my intention merely was to explain the strange rule of the priesthood or sacred kingship of Nemi and with it the legend of the Golden Bough, immortalised by Virgil, which the voice of antiquity associated with the priesthood. The explanation was suggested to me by some similar rules formerly imposed on kings in Southern India, and at first I thought that it might be adequately set forth within the compass of a small volume. But I soon found that in attempting to settle one question I had raised many more: wider and wider prospects opened out before me; and thus step by step I was lured on into far-spreading fields of primitive thought which had been but little explored by my predecessors. Thus the book grew on my hands, and soon the projected essay became in fact a ponderous treatise, or rather a series of separate dissertations loosely linked together by a slender thread of connexion with my original subject. With each successive edition these dissertations have grown in number and swollen in bulk by the accretion of fresh materials, till the thread on which they are strung at last threatened to snap under their weight. Accordingly, following the hint of a friendly critic, I decided to resolve my overgrown book into its elements, and to publish separately the various disquisitions of which {viii} it is composed. The present volumes, forming the first part of the whole, contain a preliminary enquiry into the principles of Magic and the evolution of the Sacred Kingship in general. They will be followed shortly by a volume which discusses the principles of Taboo in their special application to sacred or priestly kings. The remainder of the work will be mainly devoted to the myth and ritual of the Dying God, and as the subject is large and fruitful, my discussion of it will, for the sake of convenience, be divided into several parts, of which one, dealing with some dying gods of antiquity in Egypt and Western Asia, has already been published under the title of _Adonis, Attis, Osiris_.