Click for full poster image.

Originally published as the cover for the July 6, 1916, issue of Leslie's Weekly with the title "What Are You Doing for Preparedness?" this portrait of "Uncle Sam" went on to become—according to its creator, James Montgomery Flagg—"the most famous poster in the world." Over four million copies were printed between 1917 and 1918, as the United States entered World War I and began sending troops and material into war zones.

Flagg (1877-1960) contributed forty-six works to support the war effort. He was a member of the first Civilian Peparedness Committee organized in New York in 1917 and chaired by Grosvenor Clarkson. He also served as a member of Charles Dana Gibson's Committee of Pictorial Publicity, which was organized under the federal government's Committee on Public Information, headed by George Creel.

Because of its overwhelming popularity, the image was later adapted for use in World War II. Upon presenting President Franklin Delano Roosevelt a copy of the poster, Flagg remarked that he had been his own model for Uncle Sam to save the modeling fee. Roosevelt was impressed and replied: "I congratulate you on your resourcefulness in saving model hire. Your method suggests Yankee forebears."