The publication of Beyond Horizons comes at a significant point in the history of the Air Force, one with implications well beyond the coincident recognition of the service's 5o" anniversary. Recently the service announced its vision for the Air Force of the 21" century. Central to this vision, the leadership of today's Air Force agrees, is a transition from an air force to an air and space force on an evolutionary path to a space and air force . Clearly, as the service moves in this direction over the coming years, awareness of the roots of the Air Force's space heritage must increase and broaden. For service members, the transition necessitates a greater appreciation of this part of our history to foster an understanding of the changes currently taking place or emerging on the horizon . Scholars of Air Force history and others in the public at large similarly will gain insights into issues and events either minimized or omitted from mainstream Air Force history. Beyond Horizons promises to open the door somewhat wider to a story that to date has, for various reasons, not received the attention it deserves and requires. Unquestionably, the growing availability of official records from the earlier years of the Air Force space program will allow researchers to fill in details missing from this study and offer new interpretations of some issues and events . As the Air Force moves into its second half century, this added knowledge can only help us understand better the foundation upon which the Air Force of the ai" century is emerging.