This article examines the significance of Jacques Ranciere's work on pedagogy, and argues that to make sense of Ranciere's "lesson on the lesson" one must do more but also less than merely explicate Ranciere's texts. It steadfastly refuses to draw out the lessons of Ranciere's writings in the manner of a series of morals, precepts or rules. Rather, it is committed to thinking through the "lessons" of Ranciere in another sense. Above all, Ranciere wants to "teach" his readers something absolutely crucial about teaching. In making this claim the article emphasizes the extent to which Ranciere advocates an utterly radical pedagogy, one that completely reconceives all the central elements of "schooling", including teacher, student, intelligence and knowledge. Ranciere thinks it possible to teach without knowing; he believes that the best schoolmasters can operate not on the assumption of their expertise, but on the equality of intelligence; and this means ultimately that Ranciere contends that we can "teach what we do not know". The best schoolmasters are ignorant schoolmasters. Ranciere's radical pedagogy depends upon, just as it consistently advances, a thoroughgoing resistance to a certain form of epistemological and ontological mastery. The rejection of mastery--of schoolmasters who would know it all, and convey this knowing to their students--forms the very backbone of all of Ranciere's writings and critical investigations. This is the chief reason why Ranciere is, in a way, always talking about pedagogy, even when his subject matter appears to be something else entirely. (Contains 7 notes.)