The most eagerly awaited book in philosophy An ambitious treatment of the main theories of ethics Illuminates a wide range of issues in moral philosophy and beyond Written in the uniquely lucid and compelling style for which Parfit is famous Specially written commentaries by four eminent philosophers Two-volume set at a special price On What Matters is a major work in moral philosophy. It is the long-awaited follow-up to Derek Parfit's 1984 book Reasons and Persons, one of the landmarks of twentieth-century philosophy. Parfit now presents a powerful new treatment of reasons, rationality, and normativity, and a critical examination of three systematic moral theories - Kant's ethics, contractualism, and consequentialism - leading to his own ground-breaking synthetic conclusion. Along the way he discusses a wide range of moral issues, such as the significance of consent, treating people as a means rather than an end, and free will and responsibility. On What Matters is already the most-discussed work in moral philosophy: its publication is likely to establish it as a modern classic which everyone working on moral philosophy will have to read, and which many others will turn to for stimulation and illumination. Readership: Students and scholars of philosophy; anyone with an interest in moral philosophy