Nietzsche's On the Genealogy of Morality occupies an unstable position in philosophical thought: it oscillates between seeming damning and irrelevant. This chapter argues that Nietzsche's aim in the Genealogy is to show that modern morality has systematically broken the connection between perceptions of increased power, and actual increases in power. It introduces the currently dominant interpretation of the Genealogy, which treats the text as establishing that modern morality undermines flourishing. The chapter develops a new interpretation of the Genealogy, by offering a characterization of flourishing that explains why flourishing is normatively relevant. It shows that the will to power thesis actually does generate substantive results when it is applied to evaluative orientations, rather than discrete, context-free moral judgments. The chapter explains why, according to this interpretation, the historical form of the Genealogy is necessary rather than adventitious. The story in the Genealogy constitutes a historically grounded critique of modern morality.