Following "L'archeologie du savoir" ("The Archaeology of Knowledge") Foucault's work increasingly focused on the analysis of social institutions. "Surveiller et punir" ("Discipline and Punish") which critically acclaimed even by mainstream historians and is probably his best-received book - today it has the widest readership of all his books Because it's Actually assigned reading in universities now. Crucial to an understanding of his work as a whole. At this point Foucault had truly become to "engaged" philosopher and this is the beginning of "the later Foucault," the activist and social critic.