For the first time meaning of basic philosophical concepts of K. Marx for psychology is presented in a systematic way. The following theses are conceptualized and set forth: mind and activity constitute a dialectical unity; oppositions of the social vs. the individual, of the internal vs. the external, and of the natural vs. the social must be overcome in the psychology of man. Social-historical determinants of man's psyche and consciousness are discussed; principles of psychological study of personality-of individual motives and needs, and of general and special abilities-are outlined; and general ideas concerning building of scientific psychology as a system comprising methodological assumptions, theoretical concepts and experimental facts, and dialectically integrated in the development of a socialist society-are offered and discussed.