Last weekend Pierangelo Garegnani passed away in Rome. He was the main disciple of Piero Sraffa, and one of the most important heterodox critics of the mainstream marginalist (neoclassical) approach. A full account of his contributions to economics is well beyond what I can offer in this space, but here are a few highlights.
As early as 1961, while spending an academic year at MIT, he suggested during a presentation by Paul Samuelson that his results depended on the assumption that all sectors use the same capital-labor ratio. The final results of his critique were presented in Garegnani's paper “Heterogeneous Capital, the Production Function and the Theory of Distribution.” His paper shows conclusively that the marginalist theory of value and distribution based on an aggregate production function is untenable. This of course builds on Sraffa's work in the Production of Commodities (PC). By 1966, in the famous Quarterly Journal of Economics (QJE) Symposium, Samuelson had admitted that the neoclassical parable was not defensible.