Per Ardua Libertas. Most Secret, a printed catalogue of MI9 covert equipment,
produced to aid prisoners and operatives during WW2. Detailing different types of printed maps on fabric, escape aids including concealed compasses in coat buttons, pens and pipes, concealed hack saws. Specially designed flying boots converted which to normal footwear, convertible uniforms, innocuous domestic items and games which converted to secret message carriers, and all manner of devices whereby materials could be shipped to prisoners of war. Includes examples of printed maps, letterheads of front organisations and devices prepared to aid escaping prisoners.