Established during World War II to advise the President regarding the strategic direction of the armed forces of the United States, the Joint Chiefs of Staff (JCS) continued in existence after the war, and as military advisers and planners, have played a significant role in the development of national policy. Knowledge of JCS relations with the President, the National Security Council, and the Secretary of Defense in the years since World War II is essential to an understanding of their current work. An account of their activity in peacetime and during crises provides, moreover, an important series of chapters in the military history of the United States. For these reasons, the Joint Chiefs of Staff directed that an official history be written for the record. Its value for instructional purposes, for the orientation of officers newly assigned to the JCS organization and as a source of information for staff studies, will be readily recognized. Written to complement The Joint Chiefs of Staff and National Policy series, The Joint Chiefs of Staff and the War in Vietnam focuses upon the activities of the Joint Chiefs that were concerned with the conflicts in Indochina and later Vietnam. The nature of the activities of the Joint Chiefs of Staff and the sensitivity of the sources used caused the volumes of the series to be written as classified documents. Classification designations in the footnotes are those that appeared in the classified publication. This three-part volume describes JCS activities related to the Vietnam War during the period 1960-1968. Originally, the volume was written as a collaborative effort by members of the Historical Division; each part is being updated and published separately. In the preface, Dr. Graham Cosmas discusses the general nature of the revisions that he made in updating the text. Dr. David Armstrong edited the revised version of Part Three; Ms. Susan Carroll compiled the Index; and Ms. Penny Norman prepared the manuscript for publication. The volume was reviewed for declassification by the appropriate US Government departments and agencies and cleared for release. The volume is an official publication of the Joint Chiefs of Staff but, inasmuch as the text has not been considered by the Joint Chiefs of Staff, it must be construed as descriptive only and does not constitute the official position of the Joint Chiefs of Staff on any subject.