1956. Fourth edition. 287 pages. Pictorial dust jacket over blue cloth. Black and white photographs and diagrams. 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 mild marking and tanning. Unclipped jacket has light edge wear with minor tears, chipping and creasing. Some rubbing and marking to surfaces.