The F-22 will be the primary US Air Force air superiority fighter through the first quarter of the 21st century. The F-22 emerged from the Advanced Tactical Fighter (ATF) program. The Concept Definition (CD) phase of the ATF program began in November 1981. ATF Demonstration and Validation (D/V) was initiated in October 1986 with F-22 Engineering and Manufacturing Development (EMD) starting in August 1991. First flight of the EMD F-22 occurred on 7 September, 1997. The F-22 will enter operational service in the year 2005. This paper traces the ATF's developmental history from its earliest beginnings in the 1970s through the CD phase to the formal start of D/V at the end of 1986.