This historical monograph is one of a series of active duty and Reserve squadron histories. When completed, the series will cover each squadron in the Fleet Marine Force. This volume highlights the significant activities of Marine Fighter Attack Squadron 321 during its more than 40 years of active and Reserve service. Since its commissioning in February 1943, the squadron has evolved from a group of inexperienced wartime pilots flying F4U Corsairs to today's Reservists in their F/A-18 Hornets. During World War II, Marine Fighting Squadron (VMF) 321 enjoyed a brief, but successful, career as one of the many such units which contributed to the Allied victory in the Pacific. However, where many of its sister squadrons eventually disappeared during the postwar demobilization, VMF-321 was reborn at Naval Station Anacostia on the out- skirts of the nation's capital as the first Marine Air Reserve fighter squadron, a role in which it continues to the present day. The Reservist's role-whatever his service, but especially that of the air Reservist-is sometimes hard for the regulars and civilian population to understand, much less appreciate. While on the face of it, the Reservist appears to have the best of both worlds, he treds a thin line between his normal civilian job and family life, and his dedicated participation in his country's defense. Even though the air Reservist obviously enjoys continuing his association with military aviation, and is well paid for his time and accumulated skills, he knows he may be called upon during national crises. Such was the case during World War II and Korea. Many Reservists paid the ultimate price for their dedication; others stood by ready to fill in when called. During the volatile 1970s and 1980s, and even during the upcoming, uncertain 1990s-which, as this history is being written, has already seen the beginning of what promises to be the largest mobilization of America's military reserves since Korea-Marine Air Reservists continue to train, honing their skills, hoping they will never have to use them in earnest, but remaining ready if needed. VMFA-321 is a prime example of a Marine Air Reserve fighter attack squadron, taking pride in its long heritage and exciting future.