1982. Twentieth Edition. 545 pages. Illustrated dust jacket over blue cloth covered boards with gilt. Pages remain clear with minimal tanning and foxing. Binding remains firm. Boards have mild edge-wear with slight rubbing to surfaces. Mild crushing to spine ends. Boards have minor damp and dust stains. Book has a slight forward lean. Gilt lettering is bright and clear. Clipped jacket has moderate edge-wear with chips, tears and creasing.