1969. Sixth Edition. 1037 pages. Illustrated dust jacket over blue cloth boards. Gilt 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. Gilt lettering is bright and clear. Unclipped jacket. Panels and spine have light edgewear with tears and creases. Minor loss to spine and edges. Visible wear marks to spine and panels.