This first of two volumes on the Supermarine Spitfire covers the design, testing, development, and early WWII combat use of the famed British fighter aircraft's initial variants. The Spitfire in its original marques up to the Mk. VII provided a platform that allowed the Royal Air Force to challenge the German Luftwaffe's Messerschmitt Bf 109 and Focke-Wulf Fw 190 fighters during the 1939–1942 period of WWII. The book also covers the Seafire Marques I to III, which provided similarly valuable service for the British Navy's Fleet Air Arm.