This edition of the U. S. Army War College Guide to National Security Policy and Strategy differs from its predecessor published in 2001, The U. S. Army War College Guide to Strategy, in several respects. First, as the altered title suggests, the focus of the volume has expanded to include examination of the national security policymaking environment and process in addition to the earlier emphasis on strategy. Broadening the focus forced a necessary divergence from the tight alignment with the U.S. Army War College's (USAWC) strategy formulation guidelines that characterized the earlier volume. The guidelines are still fundamental to our approach to studying strategy and are included as Appendix I to this work --- we have simply allowed ourselves to delve more deeply into the strategic policy environment, reflected in the chart showing the Army War College Strategy Formulation Model found as a figure in the appendix. Second, the authors, with the exception of Martin Cook, are all current or recently departed members of the Department of National Security and Strategy in the War College. (Martin recently left the War College's Department of Command, Management, and Leadership.) This allows a more coordinated examination of issues in a manner consistent with our current approach to thinking about and teaching national security and strategy. Finally, we have avoided where possible reprinting articles. Some are so basic to the Army War College's approach to thinking about and teaching strategy that they reappear; most are written for this book.