Established during World War II to advise the President on 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 Secretary of Defense, and the National Security Council is essential to an understanding of the current work of the Chairman and the Joint Staff. A history of their activities, both in war and peacetime, also provides important insights into the military history of the United States. For these reasons, the Joint Chiefs of Staff directed that an official history of their activities be kept 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 is self-apparent.