This volume completes the general survey of combat operations in Korea that began with the publication in 1960 of Roy Appleman's South to the Naktong, North to the Yalu. It will be followed by a study of theater logistics and an order of battle which, along with the recently published Medics' War, will comprise the series of official Army histories of America's so-called forgotten war. Ebb and Flow records an important chapter in the Korean War. It begins with the last weeks of the pell-mell rush of United Nations forces to the Chinese border and goes on to describe in great detail the test of American military leadership and resources posed by the taxing retreat of the Eighth Army and X Corps across the frozen wastes of North Korea. It also examines the special problems posed to a fighting army during the deadly months of stalemate in the summer of 1951. The part of the war described in this volume raises many questions for the military strategist and provides a treasure trove of lessons for the student of the art of war. The book emphasizes the limitations imposed by terrain and weather on the fighting capabilities of an American army facing surprise attack from a large, disciplined enemy. The operations it describes in such careful detail will help vivify the principles of war for those who would study the profession of arms.