Keynes brought to economics a new conception regarding the positive roles social and political organizations could play in promoting economic change, in eliminating crises and stimulating growth. This chapter attempts to clarify the nature and significance of Keynesian conceptions concerning the functioning of modern economies and the adequacy of economic policies. It describes the original form Keynesianism took after World War II, with special reference to the French case. The preparation of the Sixth Plan, covering the period 1971 to 1975, clearly expressed the new strategy of emphasizing improved international competitiveness, in order either to limit import penetration or to increase French world-market shares. The chapter analyzes the limits encountered since the early seventies by traditional stabilization policies. It focuses on the limits of the Socialist strategy. The chapter stresses the main topics on the Keynesian agenda and the need for new tools and theoretical formulations toward a positive solution of the present crisis.