We investigate whether money constitutes a perfect substitute for the missing record-keeping technology in a quasi-linear environment, where private information and limited commitment are present. We adopt the mechanism design approach and solve a social planner�s problem subject to the resource constraint, the incentive constraints imposed by the existing frictions, and the
available memory technologies. The result is that when money is divisible, concealable and in variable supply, a single money may or may not be su¢ cient to replace the record-keeping technology. We further show that two monies serve as a perfect substitute for the record-keeping technology so that there is no need for a third money
