Former Trump advisor Steve Bannon is leaving his position as Executive Chairman of Breitbart News, a role he had held since 2012, the organisation said.
Trump and the White House have fiercely denounced the book by a "totally discredited" author as "fake" and full of lies.
"You hear more intelligent, mature dialogue from children in the playground," one Twitter user wrote.
Steve Bannon, Trump's ex-strategist, is portrayed as being concerned about the president's mental capacity.
Michael Wolff's 'Fire and Fury' exposé on Donald Trump and Steve Bannon promises to be one of the biggest selling political books of all time - but who is the controversial writer?
Donald Trump's lawyers hit Steve Bannon with a cease-and-desist order following revelations made about the president in a new book.
In a statement from the White House, President Donald Trump said that Bannon had "lost his mind" and had "little to do" with Trump's presidential victory.
Donald Trump's former chief strategist Steve Bannon slams Donald Trump Jr for 'treasonous meeting' with Russians in Michael Wolff's explosive new book.
Donald Trump's former strategist Steve Bannon raised sexual misconduct claims about Donald Trump and a 13-year-old girl in a Vanity Fair interview where he criticised Ivanka.
There were some very high-profile dismissals from Trump's White House in 2017 - can you name them all?
New documents reveal how Bannon and Yiannopoulos planned to thrust white supremacist and neo-Nazi values into US mainstream.
Leaked emails purport former White House strategist wanted to intel on the company's hiring process.
The actor also lashed out at Trump's former White House chief strategist Steve Bannon and called him a "p***y".
Prankster @SINON_REBORN tricks top Breitbart editor into offering to do 'dirty work'.
Breitbart was scathing in its view on Trump's 'Obama-like' Afghanistan policy.
The two week break was meant to be a reset, it was the complete opposite.
Ousted Trump adviser and Breitbart chief says: "I've got my hands back on my weapons, it's Bannon the Barbarian."
'Congrats on removing your first monument to racism!' Stephen Colbert tweeted to Trump.
A person close to the White House chief strategist claimed he handed in his resignation on 7 August.
Steve Bannon is back under the spotlight amid fresh accusations of leaking.
Former White House communications director said president's words should have been "much harsher."
Trump still can't let go of his reality TV catchphrase.