1956. Revised edition. 460 pages. No dust jacket. Black cloth. Includes various diagrams. Pages have slight foxing, tanning and minor thumbing. Foxing more noticeable towards the start and end of the book. Faint creases to some pages. Boards have some moderate edge wear, with slight bumping to corners and minor bumping to spine ends. Mildly dust-marked overall. Book has a slight forward lean.