The Rolls-Royce Merlin is the most recognisable aero engine in the world. It powered the Battle of Britain aircraft, the Spitfire and Hurricane, as they defended the shores of Britain against the Luftwaffe, foiling Hitler's plans to invade in summer 1940. It also powered the Lancasters and Halifaxes of Bomber Command as they went on their missions of destruction to the German heartland. And the ‘wooden wonder’, the Mosquito, was powered by the Merlin, its pinpoint bombing accuracy and reconnaissance work proving vital to the war effort. Retired military and commercial pilot Gordon Wilson tells the human story of the development of the engine and its operational use during the war, featuring the voices of air crew who relied on this technological tour de force.