This chapter turns to the period of the primary appearance of cultural-historical theory. The study of the role of sign mediating activity in the cultural development of higher mental functions marks the primary appearance of cultural-historical theory. Cultural development was examined by Vygotsky as a distinct line of development in relation to biological-evolutionary development. Vygotsky and his colleagues developed an experimental-genetic method for the investigation of the development of higher mental functions. Establishing a concrete human psychology in terms of drama served as a way for the theoretical and methodological refoundation of psychology as a discipline.