The book fills the gap in the psychological and psychoanalytic literature regarding the influence of horizontal connections in the family (within one generation) on the formation of personality and the development of psychopathological traits in children and adults. It is emphasized that the appearance of a new child in the family is acutely experienced by his closest brothers and sisters in age, changing the family constellation and the emotional ties that have developed in it. The insufficiently discussed and silent issues of the life of siblings are considered: violence, sexual relations between brothers and sisters, the implementation of prohibitions and taboos, sexual aspects of attachment - and more general problems: the relationship between gender and sex, the relationship between oedipal and sibling relationships, historical, ethnic and social factors in life brothers and sisters. The publishing layout is saved in PDF A4 format.