1966. Fifth Edition. 672 pages. No dust jacket. Pictorial cloth covered boards. Black and white diagrams throughout. Pages with some foxing and tanning, particularly to endpapers and textblock edges. Binding remains firm. Minor pencil inscriptions to front free endpaper. Some tape marks to pastedowns. Boards have moderate shelf wear with mild bumping and fraying to corners and crushing and fraying to spine ends. All surfaces tanned and sunned, particularly spine. Some additional rubbing marks and staining.