1961. First Edition. 174 pages. Pictorial dust jacket over red cloth. Black and white diagrams. Pages with some foxing and tanning, particularly to endpapers and textblock edges. Binding remains firm. Minor pencil inscriptions to front free endpaper. Some marginalia. Boards have moderate shelf wear with mild bumping and fraying to corners and crushing and fraying to spine ends. Some marks and staining to surfaces. Gilt lettering to spine is slightly dulled. Clipped jacket has heavy wear with tears, chipping and creasing. All surfaces heavily tanned, particularly spine.