The circumstances that have led to the production of this little book are, I think, sufficiently explained in the introductory chapter; there is, therefore, no need to dwell upon them here. It is only necessary perhaps to warn the reader that he will find in what follows but little that is original. With the exception of small contributions and suggestions upon special points, in the last few chapters alone does there exist anything that has not already found a place in the literature dealing with the subject; and probably it will be the earlier rather than the later portions of the book that will most often be consulted. Nevertheless, a work of compilation, such as the present for the most part aims at being, may have its justification and a certain sphere of usefulness; especially so perhaps in the present case, since a certain proportion of the original papers to which reference is here made is contained in books and periodicals that have at no time been readily accessible to the English-speaking public and were for some years practically unobtainable. The reader may possibly experience some surprise and disappointment at finding that, while the relations between parents and children and between brothers and sisters come in for much attention, those between husband and wife (which will probably be regarded as equally fundamental to any consideration of the psychology of the family) are but lightly touched upon. That this is the case is merely a consequence of the lines along which psycho-analytic knowledge has for the most part advanced. It is perhaps less to be regretted than would at first appear: for in the first place, the amount of consideration given to the marriage relationship has been fairly generous during recent years, while the relations between parents and children and among the junior members of the same family, have been relatively neglected: in the second place, the study of the two last named, chronologically earlier, relationships (and especially the filio-parental one) is--as will be seen--capable of throwing considerable light upon the subsequent marital relationship; it would seem probable indeed that a thorough understanding of the problems of love, sex, and marriage cannot be attained without a preliminary knowledge of the nature of the psychic bonds that unite parent and child--a knowledge that psychology is only now beginning to afford.