"Most of his senior aides didn't want him to say it."
The Age of Reagan (Vol. II): The Conservative Counterrevolution, 1980 - 1989 by
Steven F. Hayward.
This opening sentence refers to Reagan's most famous line, "Mr. Gorbachev, tear down this wall!" Hayward goes on to observe that many of those who opposed the line now claim to have been all for it -- some even claim to have written it. He uses this incident to illustrate a central thesis of his book, which is that Reagan spent as much effort working on his own team as he did battling the Democrats.
Like the first volume of Hayward's biography, this book is dense, but eminently readable. It is as entertaining as it is edifying.