Fichte's System of Ethics, published in 1798, is at once the most accessible presentation of its author's comprehensive philosophical project, The Science of Knowledge or Wissenschaftslehre, and the most important work in moral philosophy written between Kant and Hegel. Fichte's ethics integrates the discussion of our moral duties into the systematic framework of a transcendental theory of the human subject. Its major philosophical themes include the practical nature of self-consciousness, the relation between reason and volition, the essential role of the drives in human willing, the possibility of changing the natural world, the reality of one's own body, the reality of other human beings, and the practical necessity of social relations between human beings. This volume offers a translation of the work together with an introduction that sets it in its philosophical and historical contexts.