1958. Third Edition. 164 pages. No dust jacket. Blue cloth covered boards. Black and white diagrams throughout. Black and white portrait frontispiece. Pages with some foxing and tanning, particularly to endpapers and textblock edges. Binding remains firm. Dedication to front free endpaper. Boards have heavy shelf wear with bumping and fraying to corners and crushing and fraying to spine ends. All surfaces tanned and sunned, particularly board edges. Gilt lettering is dulled.