1960. Fourth Edition. 256 pages. Blue dust jacket over blue paper covered boards. Contains black and white illustrations throughout. Pages remain bright and clear with minimal tanning and foxing. Thumb-marking present. Light creasing to gutter. Binding remains firm. Boards have mild edge-wear with slight rubbing to surfaces. Soft crushing to spine ends. Light marks overall. Unclipped jacket has moderate edgewear with chips, tears and creasing. Noticeable tanning to spine. Some rubbing to surfaces. Scuffing to edges.