1946. First Edition. 144 pages. Pictorial dust jacket over blue cloth. 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. Boards have light shelf wear with minor corner bumping and crushing to spine ends. Unclipped jacket has heavy edge wear with tears, chipping and creasing. Spine noticeably sunned.