John Cunningham's wartime fame as an outstanding night-fighter ace was followed by a long career in test flying during the exciting post-war period when the jet engine was developed to power both military and civil aircraft. As chief test pilot for the de Havilland Aircraft Company he was at the leading edge of the quest for supersonic flight and in the development of the Comet, the world's first jet airliner. As Cat's-eyes Cunningham he became a household name during the bombing blitz of Britain, symbolizing the growing effectiveness of the RAF's embryonic defending night-fighter force. Few knew of his major role in perfecting the operational use of radar interception. He was the first squadron pilot in the world to shoot down an enemy aircraft using radar. His partnership with Jimmy Rawnsley, his navigator, provides a fascinating insight into the air war under the cover of darkness.