10th edition, with over 500 movement back plate illustrations. Tells you the correct strength Horolovar suspension spring to use on all clocks. Keeps repair time to a minimum with detailed information on correct assembly of the suspension unit, the mainspring size and when the clock was made by what factory. It also includes: sections on adjustment and repair of the escapement, answers to the most frequently asked questions about repairs, plus an illustrated appendix that gives information, drawings, historical facts and help for almost every clock that you will ever repair. hard cover, 200 pages.