The Condensed Analysis contains a short history of the Ninth Air Force in World War II, from the build-up before the invasion of the European continent through subsequent combat operations in 1944 and 1945. More than a narrative history, the study examines the problems that Ninth experienced in conducting joint combat operationswith ground forces across the rapidly moving battlefront in France and Germany. Some of its recommendations were implemented after World War II, others involve issues we continue to struggle with today: The need for a theater level air headquarters, command and control of tactical air forces, the importance of air-ground cooperation (including the co-location of headquarters), and the absence of the capability to mount night and all-weather operations-the lackof a "real and effective 24-hour-a-day operation." In its comprehensiveness, the Condensed Analysis also touches aircrew training and rotation, air base defense organization, civil engineering support, intelligence- virtually every one of today's Air Force specialities. Since 1945 the Air Force has gone far in creating a modernizedforce structure with highly professional personnel. Yet many of the doctrinal problems identified during World War II are still with us today. A look back, therefore, can be a useful reminder of howsuch problems developed and how they might be solved.