Scope and ContentLearning to Use the Slide Rule. Step-by-step, easy-to-follow instructions for the K12 Prep Slide Rule. K&E. Keuffel & Esser Co. Issued by Keuffel & Esser Co., New York and Hoboken, copyright 1961; issued 1961-1962. Copyright 1950. Pamphlet, 5-1/2" wide x 9" high, 21 pages plus covers. The K12 Prep (model no. 4158) was first issued in 1959 and replaced in 1962 by model 68 1892. K&E main office and factories were in Hoboken until 1968.