These papers document important aspects of Langley's scientific and administrative career. Most of the material documents the progress of his aeronautical research from his first flying model of 1891 through the failure of his Aerodrome A of 1903. Also, information files housed in the National Air and Space Museum Library include secondary accounts and photographs relating to Langley's aeronautical studies. Related materials in the NASM Library include the Stephen M. Balzer papers, 1898-1902, which consist of correspondence with Langley and his associate, Charles M. Manly, regarding Balzer's aerodrome engines.