In a recent contribution to this journal, Evelyn Forget (1990) perpetuates the misunderstandings that have surrounded Sraffa's reconstruction of classical economics. Forget contends that the interpretation of Ricardo endorsed by Sraffa (1951, 1960) and Garegnani (1984) fails to appreciate a crucial logical point concerning the relationship between outputs and long-period prices of production. From this premise she draws two conclusions: (1) that the prices established by the equations contained in Sraffa's Production of Commodities by Means of Commodities cannot coincide with Ricardo's natural prices; and (2) that the interpretation associated with Sraffa and Garegnani must therefore be wrong. But Dr Forget's premise is unfounded, and the reasoning by which she derives her conclusions is flawed. The analytical core of the classical surplus approach, as outlined by Garegnani (1984), is comprised of a set of logically necessary and mathematically exact relationships that link relative prices, the real wage and the profit rate when the technical conditions of production, the wage (or profit) rate, and outputs are specified; these relationships are summarized in the equations found in parts I and ii of Production of Commodities. By contrast, the forces that determine the real wage, the technique of production, and the social product cannot be described with the same degree of formal precision, since the magnitudes taken by the wage, the input coefficients, and the outputs do not have the status of logically necessary inferences; hence the analysis of these forces belongs more properly to a secondary stage of investigation outside the core.1