T.O. No. 02-35GC-1, Handbook of Operation Instructions for the Model R-1820-65 Engine and Associated Models. 14 p, illus, 8.5x11", no binder. Note on the front states that this should be used for flight purposes when Pilot's Handbook is not available. "Obsolete" rubber stamp on the front and North American Aviation stamp on the back. Very good.