Deutsche Erdöl AG (DEA) was Germany's leading oil corporation prior to the First World War; after the resulting loss of its foreign interests and oil concessions the company morphed into a coal and lignite conglomerate. From 1933 onwards, under contract to the German Navy, the corporation invested in producing oil from lignite. DEA was party to the policies of the Nazi regime to the extent that it participated in "Aryanizations" and projects to secure the Third Reich's economic self-sufficiency. In the course of rearmament, Austria's "Anschluss", and the company's heavy involvement in the exploitation of oil fields in countries occupied by the Wehrmacht, DEA regained its position as Germany's largest oil corporation. During the Second World War, DEA operations relied on thousands of slave labourers both inside and outside Germany. The present volume is a follow-up project to the analysis given in "Expansion at all costs. Studies on the Wintershall AG between crisis and war, 1929-1945" that the two authors published in 2020 together with Prof. Ingo Köhler.