Foucault analyzed how modern power operates not chiefly through sovereign spectacle but through disciplinary techniques of surveillance and normalization diffused across institutions - prisons, schools, hospitals, barracks - using Bentham's Panopticon in "Discipline and Punish" (1975) as a diagram of this modern disciplinary power. He developed the concept of "power/knowledge," arguing that power and knowledge mutually produce each other, and used Nietzschean "genealogy" to trace the contingent historical emergence of concepts and institutions rather than assuming their fixed essence.
Intellectual setting
Foucault wrote across a series of historical studies - of madness, medicine, punishment, and sexuality - that used archival research to denaturalize institutions and categories taken for granted in contemporary society, situating his method against both phenomenological subject-centered philosophy and Marxist accounts of ideology.
Key ideas
Disciplinary power and the Panopticon
Foucault argued that modern power operates less through sovereign displays of force than through diffuse disciplinary techniques of surveillance, examination, and normalization embedded in institutions, with Bentham's Panopticon prison design serving as the paradigmatic diagram of this productive, capillary power.
Power/knowledge and genealogy
Foucault argued that power and knowledge are not opposed but mutually constitutive, with forms of knowledge enabling and being enabled by power relations, and used genealogical method to trace how contingent historical power struggles produced concepts and institutions usually taken as natural or necessary.
Legacy
Foucault is among the most influential thinkers of the twentieth century across philosophy, history, and the social sciences; his analyses of power, discipline, and sexuality profoundly shaped subsequent critical theory, gender and queer theory, and postcolonial studies.