One of the eternal problems of mankind is that of love and hate. Why and how does it happen that we love this one of our fellow-men, feel safe in his affection, expect satisfactions of our needs from him and are attracted to him, while we hate and avoid other? Ever since the publication of Freud's first works one of the main objects of psycho-analytic research has been the study of these powerful currents of the human mind. The author contributed several important papers on this subject, and Primary Love and Psychoanalytic Technique is a collection of his material from 1930 to 1952. The first half of this volume is a collection of all his papers on this topic. The first, "Psycho-Sexual Parallels to the Fundamental Law of Biogenetics", is an attempt to trace the development of the erotic instincts from their earliest biological beginnings in unicellular organisms to their highest manifestations in human beings. Other papers deal with the problems of "Genital Love". "Transference of Emotions", of "Love and Hate" and so on.