1955. Fourth Edition. 121 pages. Yellow dust-jacket over blue cloth. Pages remain bright and clear with minimal tanning and foxing. Pencil inscription to front endpaper. Some pages are dog-earred. Boards have mild edge-wear with slight rubbing to surfaces. Spine has crushing to both ends. Book has forward lean. Clipped jacket has light edgewear with tears and creasing. Spine is heavily tanned.