THIS IS A STUDY of the monetary writings of the great neoclassical economists, dating from the early 1870's, and their significance for the development of monetary theory. Two deductive approaches to the quantity theory characterized neoclassical monetary theory. One was a utility analysis of the demand for money. This was generally heuristic, with little recognition on a formal level of the crucial proposition that holding money yields a utility of its own, as distinct from the goods and services that the money can buy. This proposition, however, does emerge, if only from the context of a clumsy exposition, hampered by the vestiges of an antimercantilist view of money. Moreover, neoclassicists provided specific rationalizations for holding cash balances. Several recognized that money is held at the sacrifice of interest. Marshall and Von Mises pointed out that the benefits of cash balances must be balanced against those from a commodity, business, or financial asset. However feeble one may regard these attempts, they imply that the demand for money is not a result of frictions or institutional considerations alone but of a decision-making process; and this is the essence of the utility approach. The second deductive approach to the quantity theory assumes initially an excess of actual over demanded real balances caused, say, by an increase in the supply of money. This sets in motion an attempt to dispose of the excess of cash balances by an expansion in in the demands for commodities and for bonds. If only the increased demand for commodities occurs, prices rise, which lowers! actual real balances until brought into equilibrium with demanded real balances. This equilibrating process was described by Wicksell, Fisher, and Von Mises. Neither Marshall nor Walras spelled it out, although it would have been analogous to what they did in their price theory. Marshall expounded an adjustment process in terms of the credit market and the discount rate that left out reference to any cash-balance mechanism, even in the bond market. A blurred distinction between bank deposits and bank credit contributed to