1956. Revised impression. 171 pages. No dust jacket. This is an ex-Library book. Blue cloth covered boards with gilt. Black and white photographs and diagrams. Ex library copy with associated labels, inserts, stamps and annotations. Pages with some foxing and tanning, particularly to endpapers and textblock edges. Binding remains firm. Boards have mild shelf wear with light rubbing and corner bumping. Some moderate marking and tanning. Gilt lettering to spine is slightly dulled.