The Coldest Winter: America and the Korean War

From book introduction:

On June 25, 1950, nearly seven divisions of elite North Korean troops, many of whom had fought for the Communist side in the Chinese civil war, crossed the border into South Korea, with the intension of conquering the entire south in three weeks. Some six months earlier, Secretary of State Dean Acheson, in a colossal gaffee, had neglected to include South Korea in America's Asian defense perimeter, and the only American forces then in the country, part of a tiny advisory mission, were almost completely unprepared for the attack. In the early weeks of the invasion, the Communist offensive was a stunning success. Every bit of news from the battlefield was negative. In Washington, President Harry Truman and his top advisors debated the enemy's intensions. Was this, as they greatly feared, an assault ordered up by the Russians? Were the North Koreans nothing but Moscow's pawns? Or was it a feint, the first in a series of what might be provocative Communist moves around the world? They quickly decided to use United States, and in time United Nations, forces to draw a line against Communist agression in Korea.

719 pages including notes, bibliography, and index.