A philosophically sophisticated introduction to Nietzsche's most widely-read book On the Genealogy of Morality has become the most common point of entry into Nietzsche's thought. It offers relatively straightforward, sustained explanatory narratives addressing many of the main ideas of Nietzsche's mature thought, such as 'will to power, ' 'nihilism, ' 'perspectivism, ' and the 'value of truth'. It also directs its attention to what is widely taken to be Nietzsche's important philosophical contribution, the critique of morality. Yet it is challenging to understand because Nietzsche intended it as an expansion and elaboration of his ideas developed elsewhere. Presupposing no prior knowledge of Nietzsche or the text Robert Guay provides the interpretive and philosophical context to make Nietzsche's thought more accessible and shows how Nietzsche's narratives engage with philosophical issues about agency, self-knowledge, historical explanation and the critique of morality. Robert Guay is Associate Professor of Philosophy at Binghamton University.