This textbook is intended to provide readers with an introduction to the German Transformation Act (Umwandlungsgesetz) and the Act on Appraisal Proceedings (Spruchverfahrensgesetz). The law on transformations, together with the related tax law on transformations, is presented in its essential features. The book begins by explaining the systematics of the Transformation Act, as well as its key concepts and procedural frameworks. It then offers a systematic overview of the various forms of restructuring-mergers, demergers, transfers of assets, changes of legal form, and cross-border transformation processes. The textbook has been comprehensively revised, systematically updated, and adapted to reflect the current state of the law. Particular attention has been paid to the expanded rules on cross-border transformations, as structured by the UmRUG in the newly created Sixth Book (Sections 305-345 UmwG), as well as to the reform of partnership law introduced by the MoPeG, which has likewise further developed the law on transformations.