In Part I of this two-part study the author traced the development of the role of the forward air controller through the early years of the war in Southeast Asia (1961-1964). The function of the air controller, however, was not unique to this conflict. Air strikes had been directed by American controllers, operating from the ground as early as 1927, when U.S. Marines supported the government of Nicaragua during its civil war. FAC's were again used by both the Axis and Allied powers during World War II, proving extremely effective in directing air strikes for both sides. During the Korean War a new wrinkle was added when the forward air controller moved into the old T-6 pilot trainer aircraft and became airborne. These controllers, known as "Mosquito" FAC's. found it much easier to see the target area from the strike pilot's perspective. thereby improving their control capability. Moreover, the FAC was able to observe enemy activity much better than a ground observer, who was limited by the nature of the terrain.Following the Korean armistice, the role of the forward air controller fell into disuse, especially during the mid- and late 1950' s, when the strategy of "massive nuclear retaliation" was adopted. Thus, when in late 1961 U.S. Army units were sent into South Vietnam, a general re-learning process took place. At first controllers began directing air strikes from the ground. But asenemy activity picked up, it became evident that the FAC could be much more responsive when airborne. Therefore, when the United States Army entered South Vietnam in large numbers in 1965-1966, its units were supported primarily by controllers flying in 0-1 liaison aircraft.The basic elements of forward air control were developed in the pre-1965 era in South Vietnam. Therefore, the problems that faced FAC's subsequently revolved around the enlargement of the FAC force to meet increased demands for their service. The theme, therefore, of this study concerns itself with early improvisation by the FAC force to meet the needs of Allied war effort. Training programs, both in the United States and in South Vietnam, underwent constant enlargement and evaluation in order to maintaina competent product for forward air control in SEA. The 0-1, considered inadequate from the beginning, underwent modification and refurbishing in order to provide an air control vehicle until the 0-2A and OV-10 arrived on the scene to supplement and eventually replace it. Coordination became smoother as the services worked more closely together to provide the best air support possible. Tactics changed as the enemy threat became more dangerous. And the role of the forward air controller vastly expanded. By the end of the conflict, the FAC's not only controlled air strikes, but flew air cover for convoys and other troop movements, dropped propaganda leaflets, performed aerial reconnaissance sorties, and supported a variety of military operations, including assisting Special Forces clandestine missions. Moreover, before the United States pulled out of Southeast Asia in 1973, the FAC role saw the introduction of jet forward air controllers to operate in high threat areas, the inclusion of C-130's, and C-123's as FACaircraft for night operations and the development of the armed FAC concept.The detailing of events included in this study could not have been accomplished without the help of dozens of Air Force officers, who willingly agreed to interviews to fill in gaps where historical records did not cover. In addition, the numerous histories, letters, messages and studies cited all contributed significantly to round out the story. Their contributions are noted in the source citations. Finally, the editorial staff of the Office of Air Force History contributed greatly to this work with their technical assistance.