1970. 3rd Printing. 539 pages. Pictorial dust jacket over blue cloth. Volume IV. Black and white illustrations throughout. Binding remains firm. Pages and illustrations are lightly tanned throughout. Previous owner's inscription to front pastedown. Boards have light shelf-wear with corner bumping. Spine is in good condition. Unclipped jacket has light edgewear with chips and creasing. Light sunning to spine and edges.