This is a very nice booklet that has the genuine standardized parts for Gruen Watches, Catalog #545. We don't know the date of this catalog but guess it to be from the 1950's. The index refers the user to the appropriate page for each model number. There are a couple of pages that show Gruen part assortments. Each movement has a photo of the assembled movement with black and white illustration of the setting parts and special notes about that model. A couple of other pages show 'Discontinued Gruen Models'. There is an interchangeable material guide that makes up much of this catalog and is very complete. It shows the interchangeability of many of the parts, including wheels, springs, arbors, balance staffs and more. The book has 38 pages and measures 6 inches by 9 inches. It is in excellent condition with only some minor wear to the corners of the pages and cover.