In preparation for the peace conference that was expected to follow World War I, in the spring of 1917 the British Foreign Office established a special section responsible for preparing background information for use by British delegates to the conference. Plebiscite and Referendum is Number 159 in a series of more than 160 studies produced by the section, most of which were published after the conclusion of the 1919 Paris Peace Conference. The introductory chapter discusses terminology and general concepts. It notes that the terms plebiscite and referendum“in their modern acceptation are of comparatively recent origin, but the idea behind them—the ultimate right of the sovereign people to exercise direct legislative power—is of great antiquity.” The study distinguishes between plebiscites and referenda on ordinary legislation, on constitutional questions, and regarding annexations. The introduction is followed by eight chapters of widely differing lengths covering historical examples of plebiscites and referenda held between 1791 and 1909 in France, Italy, Norway, Natal (South Africa), Australia, Switzerland, and the United States, as well as a referendum in Schleswig (Germany and Denmark) that was to have taken place after the Austro-Prussian War of 1866 but that was never carried out. The study is purely historical and no general conclusions are drawn. Plebiscites were used to settle a number of political and territorial questions that arose in the aftermath of World War I.