1978. Twenty-first Edition. 192 pages. Pictorial dust jacket over blue cloth boards with lettering. Contains black and white illustrations. Clean pages and illustrations with light tanning and mild foxing throughout. Binding remains firm. Boards have mild edge-wear with slight rubbing to surfaces and bumping to corners. Lettering is bright and clear. Clipped jacket. Panels and spine have light edgewear with tears and creases. Minor water mark to interior panel. Moderate tanning to flaps, panels and spine.