The object of this book, which is addressed to all cultured men and women, is to set forth the primitive manifestations of love and to throw light on those strange emotional climaxes which I have called "Metaphysical Eroticism." I have taken no account of historical detail, except where it served the purpose of proving, explaining and illustrating my subject. Nor have I hesitated to intermingle psychological motives and motives arising from the growth and spread of civilisation. The inevitable result of a one-sided glimpse at historical facts would have been a history of love, an undertaking for which I lack both ability and inclination. On the other hand, had I written a merely psychological treatise, disregarding the succession of periods, I should have laid myself open to the just reproach of giving rein to my imagination instead of dealing with reality. I have availed myself of historical facts to demonstrate that what psychology has shown to be the necessary phases of the evolution of love, have actually existed in historical time and characterised a whole period of civilisation. The history of civilisation is an end in itself only in the chapter entitled "The Birth of Europe." My work is intended to be first and foremost a monograph on the emotional life of the human race. I am prepared to meet rather with rejection than with approval. Neither the historian nor the psychologist will be pleased. Moreover, I am well aware that my standpoint is hopelessly "old-fashioned." To-day nearly all the world is content to look upon the sexual impulse as the source of all erotic emotion and to regard love as nothing more nor less than its most exquisite radiation. My book, on the contrary, endeavours to establish its complete independence of sexuality. My contention that so powerful an emotion as love should have come into existence in historical, not very remote times, will seem very strange; for, all outward profession of faith in evolution notwithstanding, men are still inclined to take the unchangeableness of human nature for granted. The facts on which I have based my arguments are well known, but my deductions are new; it is not for me to decide whether they are right or wrong. In the first (introductory) part I have made use of works already in existence, in addition to Plato and the poets, but the second and third parts are founded almost entirely on original research. E.L.