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 times of crisis 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 events in Vietnam during these years. The nature of the activities of the Joint Chiefs of Staff and the sensitivity of the sources used caused the volume to be written originally as a classified document. Classification designations are those that appeared in the classified publication. This volume describes those JCS activities related to developments in Vietnam during the period 1964-1966. At times, the role of the Joint Chiefs in events in Vietnam may appear to be submerged in the description of foreign relations, politics, economics, and other areas having little to do with military matters. However, developments in these areas provide essential background for understanding the military activity of the 1960s. Originally a collaborative effort of the entire Historical Section, JCS, the classified publication on which this volume is based was written by Mr. Willard J. Webb. The current version has been updated by Dr. Graham A. Cosmas. Dr. John F. Shortal edited the resulting manuscript; 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.