Methuen & Co London 1st edition 1955. Hard cover dust wrapper 212pp b&w plates. Dw is chipped and worn with a number of tears and some pieces missing and has been taped on both sides. Board edges have been watered but no internal water effects. Corners bumped. foxing. Else good. In his early career, Hall commanded the cruisers Cornwall and the battle-cruiser Queen Mary. Early in World War I, he was appointed Director of Naval Intelligence where he soon built up a brilliant organisation (Room 40) that devised various ruses to deceive the German High Command. He was able to tap German and Austrian lines and personally handled all communications for security. His exposure of the 'Zimmermann' telegram helped to bring America into the War.