1969. Seventh Edition Revised. 510 pages. No dust jacket. Blue cloth. Black and white illustrations throughout. Noticeable tanning to pages and text block edges; lighter to pastedowns and free endpapers. Binding is slightly loose but pages remain attached. Boards have minor corner bumping and edgewear with mild mottling, tanning and scuffing overall. Spine has minor tanning with soft crushing to ends. Book has a slight forward lean.