This is an ORIGINAL Allis-Chalmers HD 21 Crawler Tractor Operator's Manual.  (see cover pic for S/n range) This manual has super illustrations as well as having in-depth Operation, Maintenance and Specification Information on these Famous A/C tractors (see pictures for index).  The covers of this manual are in FAIR overall condition. (see pics, wear and soiling present, front cover has a tatter / rip bottom left) The spline is tight, intact, held firmly together with 2 staples.  The pages of this manual are clean and in GOOD overall condition.  (see pics, tatter from the cover has carried over to the first few pages) This manual contains 75 pages full of information that cover these A/C tractors from A to Z.  This is a great add to the collection for your A/C tractor. This manual will ship for FREE to the USA, International buyers to pay actual shipping cost.  Thanks for Viewing............................WhiteFarms1986