The historiography of the Korean War was transformed by the opening up of Soviet archives, which offered new material that challenged the older revisionist histories on why and how Stalin blessed the North's invasion of the South in 1950. Following the excellent narrative account in his 1995 book, The Korean War: An International History, Stueck has returned to assess the implications of all the new evidence for the standard questions: Why did the war take place at all? Why did the United States fail to deter the attack on the South but then intervene to save it? Why did U.S.-led forces attempt to reunify the country and then get caught out by the Chinese? He demonstrates that many of the prerevisionist answers were good: Korea was not a civil war that became internationalized but a conflict shaped from the start by international factors. At the same time, he acknowledges the importance of domestic Korean factors. Sections on the later stages of the war and the lack of further escalation are particularly valuable.