This chapter describes the British hunger blockade and economic warfare of Germany during the First World War. Economic warfare is a part of strategy, and in the years before 1914 it was the British Government's main strategic approach to the impending threat of European war. It represented a step on the road to total warfare in the twentieth century. Taken together, blockade and the broader measures of economic warfare probably contributed half of the exogenous effect on German food supply; endogenous factors probably accounted for far greater declines in food availability. The long-term shortages of key industrial raw materials and oil, partly caused by the blockade, partly by the Central Powers' declining ability to pay for imports, but mostly by their enemies' ownership of the resources, were more decisive in shifting the military balance than shortages of food.