The North American Mustang is one of the most well-studied aircraft, the subject of many hundreds or thousands of books and articles. However, much of what is commonly understood about the Mustang, particularly its early Allison-powered variants, is not entirely correct, nor entirely complete. The published record is strewn with myths and misconceptions, which have persisted across decades. The common perception of the Allison Mustang is that of a flawed and ineffective aircraft, merely a prelude to the definitive Merlin-engined versions: an aircraft scorned and rejected by the RAF and USAAF, relegated to less important tasks by both. This orthodoxy ignores the Allison Mustangs contribution in service and influence on design. By placing the creation, evolution and use of the aircraft in as full a context as possible, the truth behind many of these commonly accepted ideas emerges. Mustang: The Untold Story examines the history of the aircraft afresh, within the orbit of tactical doctrine, strategy and even politics, as well as the changing nature of World War II as the Mustang crews were fighting it. The Allison Mustang proved to be no worse than the best aircraft of the war in the roles where it found its niche. Through this new account, it is hoped that the significance of this vital aircraft can finally be appreciated.