1937. Revised Edition. 162 pages. Blue jacket over blue cloth. Contains black and white diagrams throughout. Pages are mildly tanned, but text remains clear. Noticeable marking to some pages throughout; text is not obscured. Binding is firm. Boards and spine have minimal shelf-wear, with mild corner bumping and crushing to ends. Spine and edges are slightly tanned. Noticeable marks overall. Book has a minor backwards lean. Unclipped jacket. Light tanning to spine, edges and joints. Visible bleach spotting to rear panel. Panels have light edgewear, with small tears, chips and creases, heavier to spine ends.