1973. Revised Edition. 56 pages. This is an ex-Library book. Blue paper covered boards with blue cloth to spine. Expected library inserts, stamps and inscriptions. Pages remain bright and clear with minimal tanning and foxing. Thumb-marking present. Binding remains firm. Boards have moderate edge-wear with bumping to corners and rubbing to surfaces. Visible tanning to spine and edges. Scuffing to edges. Black marks overall.