Expanding a 1982 dissertation, this study reexamines the European air war through General Carl A. Spaatz’s vantage, arguing his insistence on bombing the German oil industry and his theater‑wide leadership were decisive; it traces his development from Commandant of the Issoudun Pursuit Training Center (1917) and special observer during the 1940 Battle of Britain to the officer who in 1922 flew the sole continental pursuit group from Texas to Michigan without loss and established it at Selfridge Field, studied at the Air Corps Tactical School at Langley Field (1924), and testified in Brig. Gen. William “Billy” Mitchell’s court‑martial, then follows his shift from fighters to bombers and his enduring belief in unescorted daylight precision bombing despite British and German shortcomings. As Chief of the Air Corps Plans Section and, from June 1941, first Chief of the Air Staff, he oversaw expansion from 1,239 combat aircraft, 570 trainers, and 2,502 officers (July 1, 1939) to 2,393 combat aircraft, 10,087 trainers, and 27,446 officers (March 1, 1942). Wartime chapters cover building the Eighth Air Force base in Britain, early strikes on French targets, Eisenhower’s summons to North Africa to command Allied air power, the reduction of Pantelleria, resolution of close air support disputes, and reorganizing Mediterranean air forces amid Air Chief Marshal Arthur Tedder’s rising influence, including creation of a new southern strategic force that became the Fifteenth Air Force. From late 1943 in London, as USSTAF commander, Spaatz paired long‑range fighter escorts with an early‑1944 counter‑air offensive that emasculated the Luftwaffe before Normandy, then drove a strategic oil campaign that starved the Luftwaffe of fuel and blunted Wehrmacht mobility, and in autumn–winter 1944–1945 added Germany’s transportation network to target priorities.