Keuffel & Esser Co. Slide Rule Manual Log Log Duplex Decitrig (No. 68 2047 -- Old No. 4187S) by Lyman M. Kells, Willish F. Kern, and James R. Bland
Paperback book, 126 pages
Fair condition. The front cover has a bit of scribble in what appears to be pen. About 30 pages have writing (some in pencil, most in pen -- see pictures for some examples); the rest of the pages are clean. There are a couple of pages that have tiny nicks on the top edge (see pictures). The covers have some light wear and light creasing. Quite useable if you don't mind the writing on some pages.
See pictures for more details.
Copyright information-- Keuffel & Esser Co., 1955 (see picture for full copyright page)
If you have any questions, please let me know. Thanks for looking!