how to use... Pickett Dual Base Log Log Slide Rules by Maurice L. Hartung published by Pickett & Eckel in June 1953. The paperback manual is 8-1/2" by 5-1/2" with 90 numbered pages. The instruction manual shows some wear on the paper cover, has the original owner's name written on the cover, has some of the page numbers circled and there is some discoloration next to the metal staples on the pages. Please view all the pictures for more information.