Allen W. Wood presents the first book-length systematic exposition in English of Fichte's most important ethical work, the System of Ethics (1798). He places this work in the context of Fichte's life and career, of his philosophical system as conceived in the later Jena period, and in relation to his philosophy of right or justice and politics. Wood discusses Fichte's defense of freedom of the will, his grounding of the moral principle, theory of moral conscience, transcendental deduction of intersubjectivity, and his conception of free rational communication and the rational society. He develops and emphasizes the social and political radicalism of Fichte's moral and political philosophy, and brings out the philosophical interest of Fichte's positions and arguments for present day philosophy. Fichte's Ethical Thought defends the position that Fichte is a major thinker in the history of ethics, and the most important figure in the history of modern continental philosophy in the past two centuries.