Taking as his starting point the notion of 'bio-power', introduced both in his 1976 course Society Must be Defended and in the first volume of his History of Sexuality, Foucault sets out to study the foundations of this new technology of power over population. Distinct from disciplinary techniques, the mechanisms of power are here finely entwined with technologies of security, and it is to the 18th century developments of these technologies with which the first chapters of the book are concerned. By the fourth lecture however Foucault's attention turns, focusing newly on a history of 'governmentality' from the first centuries of the Christian era through to the emergence of the modern nation state. As Michel Sennerlart explains in his afterword, the effect of this change of direction is to "shift the center of gravity of the lectures from the question of biopower to that of government, to such an extent that the latter almost entirely eclipses the former..." Consequently, in light of Foucault's later work, these lectures represent a radical turning point at which the transition to the problematic of the "government of self and others" begins.
