Piero Sraffa (1898-1983) was the most enigmatic and philosophically the most sophisticated mind in the history of economic science. On the occasion of the 50th anniversary of the publication of the slender classic Production of Commodities by Means of Commodities: Prelude to a Critique of Economic Theory, this paper revisits the Sraffa treatise. It argues that Sraffa tried to build the foundation of an economic theory that is based on only given objective facts and which does not rely specifically on the notion of equilibrium of demand and supply and any hypothesis regarding human subjectivities such as utility functions or demand. This revolutionary project of Sraffa was lost due to a grave misunderstanding of his book by both his followers and critics, perhaps due to his cryptic style of writing but more importantly because of the dominance of the idea of equilibrium in economic theory. The aim of this paper is to rediscover the logic of Sraffa's theory of prices that does not take on board either the notion of equilibrium or demand.