This thesis analyzes the sources, subject matter and style of George Bellows' seventeen war lithographs, five paintings and five drawings of 1918. Evidence is advanced to prove that the political developments of the First World War were a decisive factor in the creation of the War Series by Bellows who otherwise had no interest in war themes. The development of Bellows' patriotic feelings, culminating in the creation of war lithographs as a response to the changes of United States policy from one of neutrality to one of full involvement in the European conflict and a state of war with Germany in April 1917, is traced in Bellows' art and political statements. For the purpose of analysis Bellows' lithographs and paintings are divided into: scenes of atrocities depicting crimes committed by the German Army in Belgium in August 1914 as described in the Bryce Report published in the New York Times on May 13, 1915; Bellows' illustrations for the war stories published in magazines in 1918; and scenes inspired by war events and war photographs. Thematic and stylistic comparisons with the works of old masters and contemporary European artists are made. The study concludes that Bellows' war lithographs and paintings are not evaluated by modern critics as enthusiastically as most of his other works. It is suggested that one of the reasons why this is so, is the fact that Bellows who painted usually scenes he had known and seen, never went to war, and thus had to rely on articles, correspondence or photographs rather than on personal observations to determine the subjects of his war lithographs and paintings.