Many books, pamphlets and magazines from the years 1914 to 1918 display a mostly unimposing mark of “Z XI”, “Z XIX”, “By”, a stylised Monument to the Battle of Nations or many other markings in a small circle or triangle o the title page. This stamp or stamp-like mark signifies that the piece of printed matter had been checked. Each of these marks stands for one of the censor’s offices that had been set up by military institutions, particularly the 25 deputy general army corps command units (Generalkommandos der Armeekorps). “Z XI” stands for the Deputy General Command of the 11th Corps in Kassel, “By”, on the other hand, is for the 1st Royal Bavarian Corps in Munich.

Only books with an export mark were permitted to be sent by booksellers to allied or neutral foreign nations and occupied areas. To this end, publishers and printers were required to submit all printed matter with no year of publication or with a year of publication later than 1913 to the responsible military command unit for checking. Literature dealing with military technology was excluded from export, as were books containing topographical information and medical literature. The Eastern Command Book Assessment Office was one of many censor’s offices and was located in the Deutsche Bücherei from 1916 to 1918. Victor Klemperer, the philologist who later became famous through his published books, was among those who made decisions on what literature could and could not be exported.