Klaus Fischer says Nazi literature emphasized "Historic Ethnicity—that is, how a group of people defines itself in a process of historical growth. Writers tried to highlight prominent episodes in the history of the German people; they stressed the German mission for Europe, analyzed the immutable racial essence of Nordic man, and warned against subversive or un-German forces—the Jews, Communists, or Western liberals." Prominent writers included: Erwin Guido Kolbenheyer ("Die Bauhutte: Elemente einer Metaphysik der Gerenwart"; The building hut: Elements of a contemporary metaphysics, 1925), Alfred Rosenberg ("Der Mythus des 20.Jahrhunderts"; The myth of the twentieth century, 1930), Josef Weinheber, Hans Grimm ("Volk ohne Raum"; People without living space, 1926), and Joseph Goebbels ("Michael", 1929).