1951. No edition remarks. 248 pages. Pictorial dust jacket over black cloth. Black and white diagrams throughout. Pages remain bright and clean with minimal tanning and foxing. Binding remains firm. Minor pencil inscriptions to front free endpaper. Boards have light shelf wear with minor corner bumping and crushing to spine ends. Gilt lettering to spine is slightly dulled. Unclipped jacket has light edge wear with minor chipping and creasing. Some rubbing and marking to surfaces.