The necessity to approach childhood as special permanently reproduced state of society and at the same time as special whole inside of it is substantiated. The childhood is complex in structure and content and functionally obligatory phenomenon with its own laws, development and self-development trends. Its principal feature is constant change-maturation-development. Real contacts of adult world and childhood are shown. Subject - object interaction principle demanding new quality of adult approach to childhood and differentiated treatment of its various periods is underlined.