This is a new critical edition of Berkeley’s 1734 (third edition, first 1713) Three Dialogues, a text that is deservedly one of the most challenging and beloved classics of modern philosophy. The heart of the work is the dispute between materialism and idealism, two fundamentally opposed positions that are embodied by Hylas and Philonous, the characters in this philosophical drama. The book is packed with brilliant arguments and counter-arguments of an extraordinarily sophisticated nature. Amid all this philosophical swordplay one would think that there could be scant room for the characters to develop any sort of personality. Yet in Berkeley’s hands, and with his literary gifts, the interlocutors are both vivid and funny. The dialogue deals with some of the most important perennial problems of philosophy, including: the materialism-idealism dispute, skepticism in rationalist and empiricist epistemology, the conflict over apriorism and aposteriorism, rationalism versus empiricism, the existence and nature of God, the philosophy of science, philosophy of mathematics, abstract general ideas, the role of perception in human knowledge, and the metaphysics of causation. This edition combines a usefully annotated version of Berkeley’s complete original text with a substantial critical introduction, a chronology of events in Berkeley’s life and career, and supplementary annotated appendices of original sources from thinkers relevant to Berkeley’s work.