In our continuing effort to document the use of airpower in Southeast Asia, we present in this volume two major contributions to the "airpower story."Monograph 4, "The Vietnamese Air Force, 1951-1975, An Analysis of its Role in Combat," was written by General William W. Momyer, USAF (Ret), former commander of air forces in Vietnam. It presents an objective review of the South Vietnamese Air Force (VNAF) and the role played by the U.S. Air Force in VNAF's short 14-year life span. To provide the necessary perspective to this complex subject, the author presents a comparative analysis of the successes and failures of airpower during the three major enemy offensives of 1968, 1972 and 1975.The conclusions touch upon some of the fundamental doctrinal principles of airpower and highlight areas that must be carefully considered in any future employment.The events presented in Monograph 5, although not directly related to the war in Vietnam, took place in Southeast Asia, and were performed by the same men, organizations, and machines which fought so gallantly in that war. It is almost a step-by-step account of the "Mayaguez Affair" and the role of airpower in its successful outcome. Particular emphasis is given to the courage anddetermination of the young helicopter pilots during the delivery and recovery of U.S. Marines from Kho Tang Island.These two monographs provide the student of airpower with an excellent case study in the tactical employment of air resources at two widely separated points in the spectrum of conflict. For the general reader, they provide a vivid and substantive discussion on the use of combat airpower and should give some understanding of the magnitude and complexity of any airpower operation, large or small.