Book excerpt: Over the last several decades, questions about practical reason have come to occupy the center stage in ethics and metaethics. The Routledge Handbook of Practical Reason is an outstanding reference source to this exciting and distinctive subject area and is the first volume of its kind. Comprising thirty-six chapters by an international team of contributors, the Handbook provides a comprehensive overview of the field and is divided into five parts: Foundational Matters Practical Reason in the History of Philosophy Philosophy of Practical Reason as Action Theory and Moral Psychology Philosophy of Practical Reason as Theory of Practical Normativity The Philosophy of Practical Reason as the Theory of Practical Rationality The Handbook also includes two chapters by the late Derek Parfit, ‘Objectivism about Reasons’ and ‘Normative Non-Naturalism.’ The Routledge Handbook of Practical Reason is essential reading for philosophy students and researchers in metaethics, philosophy of action, action theory, ethics, and the history of philosophy.