Dr. William Glenn Robertson examines the theory and practice of U.S. counterattack theory as it existed during the defense of the Pusan Perimeter in the initial phases of the Korean War. Specifically, this study focuses on the 24th Infantry Division's defense of the Naktong River in August 1950 and on the key role that counterattacks played in the defense. Relying on such primary source materials as unit journals, messages, and war diaries, Dr. Robertson analyses how well an infantry division, skeletonized by peacetime budget constraints and debilitated by heavy fighting, applied doctrine to the perilous situation in which it found itself in Korea. He concludes that, although written for heavy divisions, official doctrine both for defense and counterattack was sound, even for a unit that had been reduced essentially to a light infantry division. The difficulties encountered by the 24th Division in August can be attributed in part to the fact that it failed to follow basic tenets of that doctrine, especially those calling for centralized command and control, timely analysis of intelligence, and coordinated counterattacks on enemy flanks. The line held, but the issue was long in doubt.