From the Workshop of the Revolution (pp. 158, Berlin, 1919). A person of world-historical importance, Emil Barth (1879–1941) was the leader of the revolutionary shop stewards (revolutionäre Obleute) and the Council of the People's Deputies' most radical member. Barth recounts his bitter experience, providing an unflattering picture of the German Revolution's (mis)leadership.
“Manifest Proletkunst” (Manifesto of Proletarian Art), a text written by the Dutch artist Theo van Doesburg, published in Kurt Schwitters' periodical Merz #2 in April 1923 (Hannover, p.24-25), with signatures by leading artists of the international avant-garde (Schwitters, Hans Arp, Tristan Tzara and Christof Spengemann).
Kautsky on the phases and journals of Marxism, on occasion of the launch of Die Gesellschaft. Internationale Revue für Sozialismus und Politik (1924–33), successor to Die Neue Zeit. The journal was edited by Hilferding and later Albert Salomon. It is online here.