Mr. Taubman talked about his book Secret Empire: Eisenhower, the CIA, and the Hidden Story of America's Space Espionage, published by Simon and Schuster. Mr. Taubman argued that the American revolution in spy satellites and electronic intelligence played a major role in stabilizing the cold war and preventing a hot war. However, the emphasis on electronic surveillance led to a neglect of human intelligence sources that contributed to the disaster of September 11, 2001. Mr. Taubman also discussed in depth the U-2 incident and its repercussions.