Forging the Ninth Army -XXIX Team: The Development, Training, and Application of American Air Ground Doctrine in World War II by Christopher M. Rein, Ph.D. is the latest volume in the Leavenworth Paper series. This study tells the story of how before D-Day, the US Army developed new doctrine and training for its air-ground teams. As Dr. Rein shows, the close air support provided by these teams often proved decisive as the Allies fought their way across the Rhine and defeated Germany.40 years ago, the Combat Studies Institute published the first Leavenworth Paper, Robert A. Doughty's The Evolution of US Army Tactical Doctrine, 1946-1976. That publication inaugurated a series of studies designed to address the issues most pressing to the Army. The Leavenworth Papers were distinguished by their acute analysis rooted in rigorous research and a well-developed understanding of how military organizations operate. The series remains vital to today's professional dialogue, demonstrating how rigorous historical inquiry can facilitate the understanding of military operations, in all their complexity and variety. Christopher M. Rein's Leavenworth Paper 24: Forging the Ninth Army-XXIX TAC Team is an excellent addition to the series. This new study looks deeply into how the US Army implemented air-ground operations in northwest Europe after Operation Overlord. Based heavily on the personal papers of key leaders, unit reports, and other primary sources, Forging the Ninth Army-XXIX TAC Team shows how the Army trained, organized, and employed its air-ground teams in 1944 and 1945. Relying heavily on experimentation, testing, and objective assessment, the Army and its air forces successfully created organizations and practices that by 1945 often proved decisive on the battlefield. As Dr. Rein's study points out, this success was not inevitable. Army leaders entered World War II convinced their air-ground teams were prepared for modern mechanized warfare. After costly failures early in the war, these men revised doctrine and introduced new training techniques. This account of clear-eyed adaptation and innovation then serves as a contemporary call for continued improvement in the training and application of air-ground doctrine, in ways that might mirror the US Army's experiences in World War II. Leavenworth Paper 24, like the other studies in the series, offers critical insights from the Army's past that can illuminate the challenges of today.