The story of the United States Army is always growing and changing. Historians constantly seek to reinterpret the past while accumulating new facts as America's Army continues to be challenged on new foreign battlefields. Nor does the Army, as an institution, ever stand still. It necessarily changes its organization, materiel, doctrine, and composition to cope with an ever-changing world of current conflict and potential danger. Thus, the Center of Military History is committed to preparing new editions of "American Military History" as we seek to correct past mistakes, reinterpret new facts, and bring the Army's story up to date. This new edition of that textbook, an important element in soldier and officer education since 1956, seeks to do just that. This edition of "American Military History" builds on the previous edition, published in 2005, and expands its coverage to include an analysis of the wars in Afghanistan and Iraq up to January 2009. This expanded section is necessarily only an initial survey of the first eight years of the war on terrorism; it is far from the final word on the subject. It may take an additional decade or more to collect sufficient documents, interviews, memoirs, and other sources to know the details of military and political planning, the implementation of those plans on the global battlefield, and the impact on the Army as an institution and on the nation. The events of the past eight years are more like current events than they are history. History-the detailed telling of a story over time based upon all the extant evidence-requires more time to find and analyze the documents and facts and bring to bear on that evidence the insight that comes only from perspective. However, today's soldiers need their story told. The events in which they participate and in which they are such important elements need to be given some form and order, no matter how tentative. The Army continues to be the nation's servant, and the soldiers that make up that Army deserve their recognition. They continue to protect our freedom at great personal risk to themselves and incalculable cost to their loved ones. This is their continuing story.