The presented book is a famous philosophical and psychological study, created at the very beginning of the 20th century and many years ahead of its time, largely anticipating the development of psychology in the 20th century. The author crossed the invisible line of already established ideas and wondered what place a man and a woman occupy in the universe in general, but found that this question concerns primarily each individual person. The bisexuality of the human being was revealed to him as a property physiologically set by nature and, even more importantly, the norm of the psyche: all features of the male sex, although in a weak, barely developed state, can be found in the female; conversely, the signs of a woman are collectively contained in a man, although in a very unformed form. One of the basic structures of the psyche was highlighted - the unity of male and female in it.