As usual, Keynes's activities during 1930 were not confined to economic theory. As noted above (p. 126), he was taking an active part in the work of the Macmillan Committee on Finance and Industry—providing by the end of the year a total of eight days of ‘private’ evidence, and examining witnesses. In addition, he took an active part in the work of the Economic Advisory Council which provided advice to the Prime Minister and the Cabinet on economic questions. Keynes's approach to his ‘private’ evidence, papers and discussions for these bodies naturally reflected his current, more abstract preoccupation with the Treatise and in some cases provides good glimpses into his current theoretical development, independent of the more geological Treatise, which shows evidence of several changes of view. As this material emanates from Keynes's public activities, it naturally appears in volume xx.

One exception to the general principle outlined above would, however, appear useful. At the time Keynes finished his Treatise, he was involved with Sir Josiah Stamp, Professor A. C. Pigou, Professor Lionel Robbins and Hubert Henderson as Chairman of a Committee of Economists of the Economic Advisory Council. The discussions of this Committee and the papers circulated were of a somewhat different, more abstract, order from those of, say, the Economic Advisory Council Papers. Moreover, Keynes's major paper on the current economic position is of considerable interest. Dated one week after Keynes finally passed the pages of the Treatise, at a time when he knew of R. F. Kahn's formulation of ‘the multiplier’, this paper provides a useful indication of Keynes's state of mind at the time he finished the Treatise rather than his state of mind in the Treatise proper.