The 50th anniversary of NASA on 1 October 2008 found an agency in the midst of deep transition. In the closing year of the presidency of George W. Bush, only a month before the presidential election and in the midst of a worldwide economic crisis, the Agency was implementing a new Vision for Space Exploration intended to return humans to the Moon, to proceed onward to Mars, and to study the cosmos beyond. All of this was to be done not with new funding, but by ramping down the Space Shuttle Program that had been the centerpiece of human spaceflight for three decades and ramping up a new program known collectively as Constellation. The immediate elements of Constellation were a new launch vehicle, Ares I; an "Apollo on steroids" human capsule dubbed Orion; and the lunar lander Altair. Huge decisions were being made that would likely affect the Agency for decades to come. In short, a new era of spaceflight was dawning-or at least that was NASA's fondest hope. It was in this milieu that the History Division at NASA Headquarters commissioned oral history interviews to be undertaken with NASA senior management. This volume is the result and provides a snapshot of the thinking of NASA senior leadership on the occasion of its 50th anniversary and in the midst of these sea changes. It is all the more valuable from an historical point of view because of the large changes that have again taken place since the 50th anniversary. Since the interviews could not be done instantaneously, this volume is the result of conversations recorded during 2007 and 2008. The interviews were facilitated by Rebecca Wright and Sandra Johnson of the Johnson Space Center (JSC) in Houston, and the whole program was under my guidance as the NASA Chief Historian at Headquarters in Washington, DC. Recordings and transcripts are available at JSC and Headquarters and are now part of the Agency's considerable oral history efforts of the past several decades.