1955. Fourth Edition (Revised). 327 pages. Dust jacket over blue cloth with gilt lettering. Pages remain bright and clear with minimal tanning and foxing. Heavier tanning to front endpaper. Binding remains firm. Pen annotation to front endpaper. Boards have moderate edge-wear with bumping to corners and rubbing to surfaces. Unclipped jacket has moderate edgewear with chips, tears and creasing.