 The book that made Foucault famous, Les mots et les choses (translated into English under the title The Order of Things), is in many ways an odd interpolation into the development of his thought. Its subtitle, “An Archaeology of the Human Sciences”, suggests an expansion of the earlier critical histories of psychiatry and clinical medicine into other modern disciplines such as economics, biology, and philology. And indeed there is an extensive account of the various “empirical disciplines” of the Renaissance and the Classical Age that precede these modern human sciences. But there is little or nothing of the implicit social critique found in the History of Madness or even The Birth of the Clinic. Instead, Foucault offers an analysis of what knowledge meant—and how this meaning changed—in Western thought from the Renaissance to the present. At the heart of his account is the notion of representation. Here we focus on his treatment of representation in philosophical thought, where we find Foucault’s most direct engagement with traditional philosophical questions.