This paper offers a rereading of Foucault's much-disputed mid-career historiographical shift to genealogy from his earlier archaeological analytic. Disputing the usual view that this shift involves an abandonment of an archaeological method that was then replaced by a genealogical method, I show that this shift is better conceived as a historiographical expansion. Foucault's work subsequent to this shift should be understood as invoking both genealogy and archaeology. The metaphor of expansion is helpful in clarifying what was involved in Foucault's historiographical shift. I describe two expansions at the heart of Foucault's move. First, Foucault went from analyzing singular isolable domains of practice (such as knowledge) to analyzing the interactions between multiple domains of practice (such as power/knowledge). Second, Foucault went from an analytic which relied on a single temporal category of rupture to an analytic which invoked the relations amongst multiple temporalities, including continuity alongside discontinuity in his subsequent analyses.