Economic theory has developed greatly in the post-war period in the field of general equilibrium theory. Existence of equilibrium and its stability and optimality have been discussed carefully by experts in the field. In the purifying process, however, they have lost various ingredients which played essential roles in the pre-war theory. When I was taught the principles of economics, a first year undergraduate course, by Professor Takata in 1942, stars were E. von Böhm-Bawerk, K. Wicksell and F. A. von Hayek. All these names are not frequently mentioned in post-war general equilibrium theory.

I began my study of economics by reading Hicks' Value and Capital. As Hicks was a Paretian on the value theory and an Austrian on the capital theory, he was a key figure in connecting the post-war to the pre-war theory. In this volume I will try and formulate the type of general equilibrium theory which such economists as Böhm-Bawerk, Wicksell and Hayek were concerned with. I shall also try and extend their type of capital theory so as to make it compatible with Schumpeter's theory of money and credit. I will try to synthesize these authors' works with the spirit of clearness and rigorousness with which we worked throughout the post-war period. Of course post-war yields in the field have been taken into account in the synthesis.

Another big name is obviously J. M. Keynes who identified the existence of involuntary unemployment with the refusal of Say's law.