Contents. PART I: THE 'CAMBRIDGE' CONTROVERSY. Interest rate determinations and oversimplifyng parables: a summing up. On a change in the notion of equilibrium in recent work on value and ditribution: a comment on Samuelson. On the rates of return on investment. The rate of profit in intertempral equilibrium. PART II TECHNOLOGY. Characterization of technology in capital theory. Real Wicksell effects and regular economies. The Hamiltonian representation or static competitive or efficient allocation. PART III: FOUNDATIONS FOR NEW APPROACHES. Capital theory in the short run. Substitution along the time axis. Marx from a von Neumann viewpoint.