1971. 2nd Edition. 528 pages. No dust jacket. Blue cloth. Includes various diagrams. Pages have slight foxing, tanning and minor thumbing. Pencil inscriptions to front endpaper. Upper text block edge foxed and dusty. Boards have some moderate edge wear, with slight bumping to corners and minor bumping to spine ends. Boards a little rubbed and marked overall. Impressions of writing to spine.