In the philosophy of Nietzsche, Karl Barth discovered an irritation force of a radical philosophical reality theory, that hides behind harsh polemics. This irritation power focuses on the question of the purpose of the human being. In the theological discourse with Nietzsche, Barth realised the necessity of an ultimate justification of being, which radically opposes a "will to power". Therefore, in his work Barth explains the meaning, the whence and the whereabouts of life in contrast to the (post)modern worldview of Nietzsche. In his study Martin Böger portrays Nietzsche's reception in all of Barth's works and analyses them with regard to his theological biography.