1946. Revised second edition. 109 pages. No dust jacket. Blue cloth covered boards. Black and white diagrams throughout. Pages and binding are presentable with no major defects. Minor issues present such as mild cracking, inscriptions, inserts, light foxing, tanning and thumb marking. Overall a good condition item. Boards have mild shelf wear with light rubbing and corner bumping. Some moderate marking and sunning. Book has slight backwards lean.