This is a rare and out of print book that is highly sought out by calculator collectors.  It is titled “The Calculating Machines (Die Rechenmaschinen) Their History and Development" by Ernst Martin, translated and edited by Peggy Aldrich Kidwell and Michael R. Williams, reprinted by The MIT Press in 1992.  It is hard bound, with 359 pages and 319 black & white drawings of calculating machines.  This book is the most important and useful reference book on mechanical calculators for collectors, now completely out-of-print and unavailable.  It is in fine overall condition.