In the 1930s one was aware of two great evils - mass unemployment and the threat of war.

The frontiers of knowledge in the various fields of our subject are expanding at such a rate that, work as hard as one can, one finds oneself further and further away from an understanding of the whole.

In Oxford before the war, I had, with this interest in mind, written a short textbook entitled, An Introduction to Economic Analysis and Policy. It was now my intention to rewrite this work.

But my shift to the serious study of economics gradually weakened my belief in Major Douglas's A+B theorem, which was replaced in my thought by the expression MV = PT.

From 1931 to 1937, I was a Fellow and Lecturer in Economics at Hertford College, Oxford.

My job was to teach the whole corpus of economic theory, but there were two subjects in which I was especially interested, namely, the economics of mass unemployment and international economics.

My interest in economics has always been in the whole corpus of economic theory, the interrelationships between the various fields of theory and their relevance for the formulation of economic policy.