The information in this history of the 7th Bombardment Group, United States Air Force, is based on official records and on the diaries and memories of former members of the Group who submitted accounts of their experiences to the author for inclusion in the book. Generally unknown and unrecognized is the fact that the 7th Bombardment Group has a rich history which is closely related to the Air Service of World War I and to the powerful United States Air Force into which the Air Service evolved. The history of a military unit is composed of the activities and accomplishments of the people and the subordinate components that, at one time or another, are assigned to it. The history of the 7th Bombardment Group dates back to World War I. Many of the men assigned to or associated with the Group were air pioneers whose activities contributed to the formation of an organization which one day would become the world''s strongest and most modern air force. While "Four Decades of Courage" focuses primarily on the history of the Seventh Bombardment Group from the beginning of World War I until 1945, the author recognizes that the history of the Group closely parallels and has played an important part, not just in the history of the United States Air Force, but also in the development of flight itself. For that reason, wherever it is practical to do so, the author has included a history of flight from its very beginning.