1928. Third Revised Edition. 340 pages. No dust jacket. Red cloth with gilt lettering. Black and white photographic frontispiece. Black and white photographic plates and graphs throughout. Light foxing and tanning to pages overall. Previous owner's inscription in pen to front free endpaper. Stickers to rear pastedown. Binding remains firm. Boards have minor corner bumping and edgewear with visible scuffing overall and light sunning to edges. Sticker to rear board. Spine has moderate sunning with soft crushing to ends. Lettering remains bright and clear. Book has a slight forward lean.