This is the milestone official comprehensive history of the United States Air Force with compelling stories about America's airmen and their aircraft. This document, Volume I, contains the first 12 chapters and begins with balloons and the earliest heavier-than-air machines. It carries the story through World War II to the establishment of the United States Air Force as a service separate from, but equal to, the Army and the Navy.Contents: Part I: The Early and Interwar Years, 1907-1939 * Part II: World War II, 1939-1945 * Part III: Building the Air Force, 1945-1950 * Chapter 1 - The Roots of U.S. Military Aviation * Chapter 2 - The Air Service in the Great War * Chapter 3 - From Air Service to Air Corps: The Era of Billy Mitchell * Chapter 4 - The Coming of the GHQ Air Force, 1925-1935 * Chapter 5 - The Heyday of the GHQ Air Force, 1935-1939 * Chapter 6 - Reaction to the War in Europe * Chapter 7 - The Army Air Forces in Desperate Battle, 1941-1942 * Chapter 8 - Building Air Power * Chapter 9 - The Defeat of Italy and Germany * Chapter 10 - Victory over Japan * Chapter 11 - The Quest for Independence * Chapter 12 - Framing Air Force MissionsHistory is therefore important to the Air Force; the recorded past is a foundation for doctrine, policy, strategy, tactics, equipment development, organization, force structure, and virtually every other element of air power. This volume, published in commemoration of the fiftieth anniversary of the Air Force as an independent service, is especially valuable. Not only should it both inspire and enlighten the members of the Air Force, it should also serve as a convenient source of information for those outside the service who are interested in the origin, growth, evolution and application of American air power.Throughout its first century, military aviation helped advance the interests of the United States. From a curiosity, fragile and of uncertain value, the warplane has become a devastating weapon. Moreover, ballistic missiles and surveillance satellites have joined aircraft in this aerial array. In these volumes, we try to describe and analyze, in the context of national policy and international rivalries, the evolution of land-based air power since the United States Army in 1907 established an Aeronautical Division responsible to the Chief Signal Officer. This work, in addition to commemorating the Air Force's fiftieth anniversary, also commemorates almost one hundred years of progress in the design and use of aerial weaponry. By placing airmen and their machines in an appropriate context, it provides a clearer understanding of the central role of the Air Force in current American defense policy.Early in the conceptualization of this work, we decided that a collaborative effort would make the best use of whatever special skills or knowledge each of us might possess. We knew, however, that successful collaboration requires a plan, and the blueprint was the work of Warren A. Trest, then the chief of the Histories Division, Office of Air Force History. He devised a basic outline for the book, and after his transfer elsewhere in the Air Force history program, Bernard C Nalty saw the design through to its completion. Under the general guidance of these two, we wrote, reviewed, and revised each chapter. A panel of historians and military officers reviewed the manuscript, which then underwent the final revisions that these distinguished individuals suggested.