1946. First Edition. 65 pages. No dust jacket. Red cloth. Includes four diagrams. Pages have slight foxing, tanning and minor thumbing. Previous owner's inscription to front endpaper. Slight warping to some pages. Boards have some edge wear, with moderate bumping and fraying to corners, while spine ends are slightly crushed and frayed. Rather scratched, rubbed and water stained overall. Various dents and droplet marks.