HMSO, March 1939. 260 pp., with 91 figure drawings + 39 full-page fldg., photo & other plates, some of which are fully cold., + 25 loose pages of amendments from Sept., 1942 and December 1942, tipped-in at the rear. Original boards ; cloth spine ; 24 x 15cm. Front hinge pulled and a little cracked at ends a page in but no damage along the e.p., join ; some typical light wear to covers but overall V.G. Stated on the front cover "Not To Be Published", this a confidential War Office instruction handbook for the Ordnance, Q.F. 3.7-inch Howitzer, Mark I on Carriages, 3.7-inch Howitzer, Marks I, II, III and IVP, land service 1939. Ninety-one labelled figures accompany a wealth of detailed narrative on the various components but the real feature of this item are the thirty-nine folding plates at the rear which are comprised of both photographs and illustrations and some of the drawings are strikingly coloured in full. Together with some loose pages of amendments from 1942, this is an extremely important wartime record of a World War II gun. Includes detailed notes on ordnance, mobile cartridges, ammunition, artillery trailers, stores, markings on ammunition, list of stores carried on vehicles, care and preservation guide, general instructions, etc. RARE.