1956. Fourth edition. 892 pages. Pictorial dust jacket over red cloth. Black and white diagrams throughout. Pages with some foxing and tanning, particularly to endpapers and textblock edges. Some cracking to gutters with exposed netting. Binding slightly loose. Title page detaching. A previous owner's name to front free endpaper. Boards have mild shelf wear with light rubbing and corner bumping. Some light marking and tanning. Unclipped jacket has heavy edge wear with tears, chipping and creasing. Some tanning and foxing to all surfaces, particularly to spine.