The article is dedicated to the book of J.M. Keynes “The General Theory of Employment, Interest and Money”, which was published 80 years ago but still remains relevant. The article deals with several theoretical concepts which made an essential impact on economic theory and praxis. Further developed by Keynes’ apprentices and followers, these ideas and method continue to “work” in the framework of 21-st century economy. The Keynesian theory provides cognitive basis and analytical tools to modern research trends, — particular interest to psychological aspects of economic behavior, to the issue of existence of equilibrium in non-equilibrium economics, non-linear trade-off of conflicting forces at the spontaneous markets as well as adjusting role of government policy. The author dwells upon the Keynesian analysis of psychological factors in “The General Theory” and their key role in shaping of economic reality.