Alexander Gardner (1821–1882) was born in Scotland and later trained as a jeweler. He immigrated to New York in 1856 and soon went to work for the photographer Mathew Brady (ca. 1823–1896), teaching him how to make salt prints and managing Brady's Washington, D.C. studio. Gardner left the Brady Studio in 1862 after a dispute over print attribution and copyright and became the official photographer for the Army of the Potomac under General George McClellan. Although he published over one hundred of his war views in Gardner's Photographic Sketch Book of the American Civil War (1866), the volume was not a financial success and almost bankrupted him. Gardner continued his documentary photography projects in his later life. In 1867, he was hired by the Kansas Pacific and Union Pacific Railroads to document the building of a rail route to California, and in 1868, he photographed the Fort Laramie Treaty Council where he was the first photographer to make images of the Plains Indians in their home territory. During the 1870s, the artist ran a photography studio in Washington, D.C., where he photographed members of American Indian treaty delegations.