The foreword states "In this chronology, Air Force manned space flight activity is viewed from the perspective of the ballistic missile development agency - the Air Research and Development Command's Western Development Division, later re-named the Air Force Ballistic Missile Division. Due to resource limitations at the Space Systems Division historical office, research for this chronology has been generally limited to materials available in the files of that office. All documents cite in the notes which follow each entry are located in the archives of the Historical Division, Office of Information, Space Systems Division, in Los Angeles California." There are handwritten notes throughout.