In 1775, Tetens had already attempted to consolidate metaphysics - even before such contemporaries as Lambert and Kant. By drawing on empiristic as well as rationalistic traditions, he developed the idea of a philosophical>Grundwissenschaft< (universal foundational science) and explains the necessity, goals and form of this. This volume is not only useful for those doing research on Tetens; it is also a key to late Enlightenment philosophy in Germany in the 18th century. This new edition, with a text-critical apparatus and explanations of the subjects provides a revised text. It contains contemporary recensions, a comprehensive Tetens bibliography as well as material on his life and work, among which is a list of Tetens' lectures along with compendia of these.