1967. Seventh impression. 108 pages. Pictorial dust jacket over green cloth. Black and white diagrams throughout. Pages remain bright and clean with minimal tanning and foxing. Binding remains firm. Small bookshop label to front free endpaper. Boards have light shelf wear with minor corner bumping and crushing to spine ends. Some mild marks and staining to surfaces. Unclipped jacket has light edge wear with minor tears, chipping and creasing. Some rubbing and water marking to surfaces.