Why do presidents cooperate with Woodward on books about them?

FROM CNN's Jack Cafferty: In 1974, Bob Woodward and Carl Bernstein brought down the presidency of Richard Nixon with their reporting on Watergate. [cnn-photo-caption image=http://i2.cdn.turner.com/cnn/2010/images/09/23/art.book.jpg caption="The cover art for Bob Woodward's latest book: 'Obama's Wars’"] But Bob Woodward was just getting started on the occupants of the White House. In 1994, he wrote "The Agenda" … Continue reading Why do presidents cooperate with Woodward on books about them?