ABOUT THIS ARTICLE

This article is based on separate interviews that the authors conducted with Robert McNamara and McGeorge Bundy, the final interviews before the two men's deaths.

Bob Woodward interviewed McNamara for 2 1/2 hours on Aug. 7, 2007, at McNamara's Watergate apartment. McNamara agreed that the interview was on the record but at several points said he did not want to be quoted. His wife, Diana McNamara, was present for the entire session. After his death this summer, she agreed that all his comments should be published.

Gordon M. Goldstein interviewed McGeorge Bundy multiple times from the spring of 1995 to Sept. 11, 1996, five days before Bundy's death. Goldstein was collaborating with Bundy on a memoir and analysis of presidential decision-making during the Vietnam War.