History is replete with examples of nations suffering catastrophic military defeat to adversaries who were able to achieve surprise at the strategic level. In retrospect, it seems clear that all the critical warning signs were available in advance. In considering these events, the worthwhile question ultimately becomes this: Why was the essential, known information either ignored or discredited? How was it, for example, that the Russians in June 1941, the Americans in December 1941, the United Nations Forces in October 1951, and the Israelis in October 1973 failed to correctly perceive reality? And, if lessons can be gleaned from these and other historic examples, what conclusions might be drawn by U.S. leaders today—particularly as the nation faces increased competition with China?