Trump said he never granted Wolff an interview for the book and blamed former adviser Steve Bannon, who he called "Sloppy Steve", for granting Wolff access at the White House.
"My support is also unwavering for the president and his agenda - as I have shown daily in my national radio broadcasts, on the pages of Breitbart News and in speeches and appearances from Tokyo and Hong Kong to Arizona and Alabama".
"I regret that my delay in responding to the inaccurate reporting regarding Don Jr has diverted attention from the president's historical accomplishments in the first year of his presidency".
"The one description that everyone gave, everyone has in common - they all say 'he is like a child.' And what they mean by that he has a need for immediate gratification".
"I went from VERY successful businessman, to top T.V. Star to President of the United States (on my first try)".
Wolff, who has come under heavy criticism from the White House for the book, said he did not leave out positive perceptions of Trump in order to paint a negative picture him.
As Guy noted, Bannon made several colossal errors which predicated his downfall from Trump's so-called grace.
He also criticized Bannon, who is quoted at length by Wolff, saying it was "tragic and unfortunate" that Bannon "would make these grotesque comments so out of touch with reality and obviously so vindictive".
Wolff said White House staffers he talked to would say things like "we're not at a 25th Amendment level yet".
Chatter about Mr Trump's mental fitness for office has intensified in recent months on cable news shows and among Democrats in Congress.
Michael Wolff, the author of "Fire and Fury", said Sunday that the 25th Amendment, which would allow the president's cabinet to remove him from office, is "alive every day in the White House". The White House has called the publication "fiction". It didn't exist, OK?
"The story that I have told seems to present this presidency in such a way that it says he can't do his job", Wolff said.
Bannon apologized Sunday, saying that Trump Jr.
Reagan died in 2004, aged 93, from pneumonia complicated by the Alzheimer's disease that had progressively clouded his mind. Reagan announced his diagnosis in a letter to the American people in 1994, more than five years after leaving the White House.
Donald Trump too has continued to fight back against the book.