In this lecture given at the College de France in 1977-1978, Michel Foucault proposes to elaborate on what he had called at the end of «Il faut défendre la société»a security dispositive. He proposes to analyse the transformation of modes of government successively focusing on the territory (sovereignty) on the body (discipline) and finally on the population (biopolitics). This helps us to think the transformation of control: the focus is not so much on the territory or on the body but on the population itself.
Foucault Michel,Sécurité, Territoire, Population, Paris, Seuil/Gallimard, 2004.