Derek Parfit was one of the world's leading philosophers. His On What Matters was the most eagerly awaited book in philosophy for many years. Reading Parfit: On What Matters is an essential overview and assessment of volumes 1 and 2 of Parfit's monumental work by a team of international contributors, and includes responses by Parfit himself. It discusses central features of Parfit's book, including the structure and nature of reasons; the ideas underlying moral principles; Parfit's discussions of consequentialism, contractualism and Kantian deontology; and his metaethical ideas and arguments. Reading Parfit will be central reading for students of ethics and anyone seeking a deeper understanding of one of the most important works of philosophy published in the last fifty years.