The first volume provides readers with a completely new edition of the second version of Fichtes system. Krauses manuscript forms the basis of this text and was newly checked for this edition. For the first time, the other student transcripts are systematically made use of. This novelty, the addition of numerous improvements, and additional or comparative passages enhance the philological and philosophical accuracy and richness of the textual basis. The second volume offers for the first time the complete corpus of all texts referring to this version of the doctrine of science (excerpts from published writings, revisions and relevant passages from the correspondence). The study of one of Fichtes most important texts will be facilitated by means of a detailed introduction.