The purpose of this paper is to reconstruct Foucault’s reflections on the birth of modernity, paying particular attention to the role of capitalism and discipline within it. The thesis we will defend is that in Foucault’s work in the first half of the 1970s—especially between 1973 and 1975—both dimensions appear as two aspects of the same continuum, thus establishing a necessary link between them. This approach, which contests certain Marxist positions, attempts to reveal that the research on disciplinary power can be conceived as a complement, and not a correction, of the analyses deployed by Marx in Das Kapital.