1941. 2nd edition. 55 pages. No dust jacket. Stiff blue card boards. From the Aeronautical Engineering series, ground engineers. Pages have slight foxing, tanning and minor thumbing. Previous owner's inscription to front endpaper and pastedown. Boards have some moderate edge wear, with slight bumping to corners and minor bumping to spine ends. Boards a little rubbed and marked overall. Small hole to rear joint.