London, 15 September 1940. In and out of the clouds above the British capital, one of the most decisive battles of the Second World War was taking place. The Luftwaffe's massive air assault aimed to force Britain to sue for peace or, by seizing air superiority, make possible the cross-Channel invasion Hitler's generals were planning. Churchill himself watched the climactic battle unfold from the RAF operations room in Uxbridge. He asked what reserves the British had in the battle over London: 'There are none', came the reply. Every available squadron was in the air. The air battle over Britain shaped the course of the entire war. But the fight that day was itself shaped by the duel between the two most advanced types of warring fighter planes: the British Supermarine Spitfire and the German Messerschmitt Bf 109. In this remarkable new book, David Isby looks at the clash between these two fighter planes, lasting from pre-war development to decisive combat. The Decisive Duel tells the stories of these iconic, classic aircraft and also the people who created them: Willy Messerschmitt, the German designer with a love for gliders and admiration for Hitler; RJ Mitchell, his brilliant British counterpart, who struggled against illness to complete the design of the Spitfire. In fascinating detail, Isby describes the crucial role the two opposed planes played, from the drawing boards, to Dunkirk, the Battle of Britain, to the final battles over Germany. In today's Britain, the Spitfire's story is particularly resonant both for its wartime achievements and its continuing potency as a symbol of victory. Accessibly written and impeccably researched, The Decisive Duel is both a wonderful work of aviation history, and a valuable insight into the duel between two fighters that shaped the Second World War.