Bob Woodward exposes one of the final pieces of the Richard Nixon puzzle with the untold story of Alexander Butterfield, the Nixon aide who disclosed the secret White House taping system that changed history and led to Nixon's resignation. In forty-six hours of interviews with Butterfield, supported by thousands of documents, many of them original and not in the presidential archives and libraries, Woodward has uncovered new dimensions of Nixon's secrets, obsessions, and deceptions.