[AMUNDSEN, Roald (1872-1928) and ELLSWORTH, Lincoln (1880-1951), subjects]. Air Pioneering in the Arctic. The Two Polar Flights of Roald Amundsen and Lincoln Ellsworth. Part I The 1925 Flight From Spitzbergen to 88 North / Part II The First Crossing of the Polar Sea, 1926. New York: National Americana Society, 1929. Folio. Profusely illustrated with photogravures and maps. 126 pp. Plate leaves unpaginated. Publisher's full light blue cloth, front board and spine lettered in gilt, publisher's matching blue cloth slipcase (spine of book is toned and soiled, some rubbing, soiling to boards, some toning, foxing to endleaves, some occasional offsetting to illustrations; slipcase worn, soiled, toned with some splitting, bumping). Very good. THE RARE FIRST EDITION OF THIS COLLECTION OF PHOTOGRAVURES OF AMUNDSEN AND ELLSWORTH'S POLAR FLIGHTS IN THE UNCOMMON SLIPCASE.