Written during 1969, this essay criticizes Althusser’s interpretation of the ‘mature’ Marx as breaking with the influence of Hegel and with the concept of alienation. Without denying the discontinuity in Marx’s thinking, Mandel thought Marx based his analysis on a materialist interpretation of Hegel’s dialectic. Mandel argued that rather than abandoning the notion of alienation, Marx changed this concept from an anthropological to a historical, materialist one. A ‘call to revolutionary action by the proletariat’ replaced a ‘philosophical conclusion on the plane of thoughts, ideas, intellectual work’. Althusser however had transformed Marxism into something ‘static’, without understanding that its basis is ‘the historically perishable nature of all ‘structures’’. Writing in the aftermath of May 68, this was a discussion that for Mandel had direct political implications.