New edition. 62 pages. Pictorial dust jacket over brown cloth. Black and white diagrams throughout. Pages with some foxing and tanning, particularly to endpapers and textblock edges. Binding remains firm. Minor pencil inscription to front free endpaper. Boards have light shelf wear with minor corner bumping and crushing to spine ends, but heavy creasing to front. Gilt lettering to spine is slightly dulled. Boards are slightly bowed. Unclipped jacket has heavy edge wear with large tears, chipping and creasing. All surfaces heavily tanned, particularly spine.