than marginal influence on US economic policy only after 1939. Keynes's magnum opus, The General Theory of Employment, Interest and Money was published in 1936. It was researched and indexed by one of Keynes's favourite students, later the economist David Bensusan-Butt. The work served as a theoretical justification for the interventionist policies Keynes favoured for tackling a recession. Although Keynes stated in his preface that his General Theory was only secondarily concerned with the "applications of this theory to practice," the circumstances of its publication were such that his suggestions shaped the course of the 1930s. In addition, Keynes introduced the world to a new interpretation of taxation: since the legal tender is now defined by the state, inflation becomes "taxation by currency depreciation". This hidden tax meant a) that the standard of value should be governed by deliberate decision; and (b) that it was possible to maintain a middle course between deflation and inflation. This novel interpretation was inspired by the desperate search for control over the economy which permeated the academic world after the Depression. The General Theory challenged the earlier neoclassical economic paradigm, which had held that provided it was unfettered by government interference, the market would naturally establish full employment equilibrium. In doing so Keynes was partly setting himself against his former teachers Marshall and Pigou. Keynes believed the classical theory was a "special case" that applied only to the particular conditions present in the 19th century, his theory being the general one. Classical economists had believed in Say's law, which, simply put, states that "supply creates its demand", and that in a free market workers would always be willing to lower their wages to a level where employers could profitably offer them jobs. An innovation from Keynes was the concept of price stickinessthe recognition that in reality workers often refuse to lower their wage demands even in cases where a classical economist might argue that it is rational for them to do so. Due in part to price stickiness, it was established that the interaction of "aggregate demand" and "aggregate supply" may lead to stable unemployment equilibriaand in those cases, it is on the state, not the market, that economies must depend for their salvation. In contrast, Keynes argued that demand is what creates supply and not the other way around. He questioned Say's Law by asking what would happen if the money that is