The Economics of Illusion, Hahn's earlier concentrated attack on Keynes, is followed now- for professional economists and those concerned with money theory- by a positive, declarative statement of Hahn's own position. Or rather, his private working model of the economic universe- a working model ""simple enough to clarify the fundamental relationships between various economic data"" Hahn builds from the ground up. Yet each of his own contentions seems in some form to derive from, answer to, or react against some Keynesian tenet. Hahn charges Keynes with misplaced emphasis, as when ""long-run economic forces, such as the prospensity to work, are completely eclipsed by... the propensity to consume"". Hahn regards the position of Keynes as not extensive enough to comprise a full economic theory nor adequate in ""short-run developments"". There is a continuous cycle of return from Hahn to Hahn-leveling-at-Keynes, and it's hard to say how much that is new and useful sifts through the layers of rancor. Comments on the nature of the business cycle will be a feature for investors.