Scope and ContentK&E Polyphase Duplex Decitrig Slide Rule No. 4071. A Manual. By Lyman M. Kells, Willis F. Kern and James R. Bland. Published by Keuffel & Esser Co., New York & Hoboken, N.J., [copyright 1939], issued circa 1949 to possibly 1952. Booklet, 5-1/4" x 7-11/16" high, pp [iv], 87, [2]. With printed paper band: "This Manual, Polyphase Duplex Decitrig No. 4071, applies to Doric Plastic Slide Rule No. 9071." Center text is a "Note" that refers to manual descriptions that apply to the 4071 and the 9071. (Band is 3-1/8" high) The Doric line was issued only from 1949-1952 and the 9071 is only known by an appearance in a replacement parts list found in the 1949 catalog. It appears that few examples are known. Although issued 1949 or later, the cover has the old K&E griffin trademark. The paper band is in the colors and typeface used by K&E from the ca. 1940s.