The seventh volume of the "Communications" of the German-Russian Historical Commission is dedicated to the "Ur-Catastrophe of the 20th Century" (George F. Kennan), the First World War, which is currently being discussed again. It documents a total of 18 contributions from the colloquia held in Moscow in 2013 and in Berlin in 2014. Renowned historians illuminate various aspects of this devastating war in the European context, focusing not only on Germany and Russia but also on England, France, Italy, the Ottoman Empire, as well as Austria-Hungary and its successor states. The volume includes essays by the following authors, as usual in both German and Russian: Helmut Altrichter, Bernhard Bachinger, Vladimir Buldakov, Bernd Faulenbauch, Vasilij Dudarev, Manfred Hildermeier, Johannes Hürter, Stefan Karner, Lothar Kettenacker, Valerij Ljubin, and Viktor Mal'k.