help with book

can any one help with a book i bought at a car boot at the weekend, its
called AIRCRAFT of the FIGHTING POWERS volume 1 - 1940 aircraft
compiled by H. J. COOPER and O. G. THETFORD edited by D. A. RUSSELL
published by THE HARBOROUGH PUBLISHING CO LTD

seems to have been published in 1941 (looking on the net) but not sure ,
then there is the fifth and sixth impressions iv found ( think this might be
the addition they are) but there is nothing like this printed in my book at
all ( is it a first addition iv got ) any help would be grateful about this
book

thanks Paul