The opening of Introduction
The sexuality of the modern civilized man--the sum, that is to say, of the phenomena of sexual love dependent upon and associated with the sexual impulse--is the result of a process of development lasting many thousands of years. Therein, as in a mirror, we may see an accurate reflection of all the phases of the bodily and mental history of the human race. Anyone who wishes to understand modern love in all its complexity must, in the first place, succeed in informing himself, not merely regarding the first foundations of the feeling of love in the grey primeval age, but, in addition, as to the manner in which that feeling has been transformed and enriched in the course of the history of civilization. For modern love is a complex of two constituents.