In this article I present Claudio Napoleoni’s Lectures on Marx’s Theories of Surplus Value, given in his course in Turin during the 1972-73 academic year, which are collected in an Italian book edited by me and published in 2024. Napoleoni used in the classroom the Kautsky edition (the only one available in Italian in its entirety at the time), rather than the IMEL edition of the 1950s (which was later published in Italian under the editorship of Cristina Pennavaja) or the MEGA 2 version in The Economic Manuscript of 1861-73. These Lectures highlight Napoleoni’s radical interpretive turn which occurred since mid-1971 and show the main features of his research program aiming at a rehabilitation of Marx’s value theory of (abstract) labour, both in its qualitative and quantitative aspects. The main points of the course are discussed in the article: from the discussion of Physiocracy, Smith and Ricardo, to the confrontation with Bailey’s criticism of Ricardo, ending with the discussion of crisis and Ricardian socialism. The notion of ‘absolute value’ is particularly relevant. Napoleoni is one of the very few who saw its essentiality in the critique of political economy (and its internal connection with ‘money as a commodity’ to ground the argument that value exhibits nothing but labour), getting the profound distance from Ricardo’s version of the seemingly similar concept. Napoleoni’s understanding, however, was fraught with confusion and uncertainty. The role of fetishism (as distinct from fetish-character), of dialectical contradiction (and hence of Hegel), and the particular meaning of critique (as opposed to criticism), are discussed.