Author, author: who is Michael Wolff - the writer behind this instant bestseller?
The man behind the explosive insider's take of Donald Trump's White House is a 64-year-old New York socialite who has built a career documenting the rich and powerful.
Michael Wolff, a balding and bespectacled journalist with a sharp tongue, has previously written books on Rupert Murdoch and other big-media "money guys".
His acerbic columns for magazines and newspapers over the years have become known for their "first-class gossip" and unrivalled access to those in the know.
The writer has at times become the source of media attention himself, not least over his divorce and a new relationship with a woman 30 years his junior.
But it is the method behind Wolff's vivid accounts that has been thrust into the spotlight after his new book, Fire and Fury: Inside the Trump White House, sent shockwaves through Washington.
Questions about the accuracy of past pieces have emerged amid a fierce rebuttal of the book from the White House, which has dubbed it "trashy tabloid fiction".
Wolff, whose mother was a newspaper reporter and father an advertiser, began his journalism career as a copy boy for The New York Times.
The decades that followed saw freelance articles and columns, an attempted novel, moves to buy the New York Magazine and internet entrepreneurialism.
His best-known book before last week was a biography of media mogul Rupert Murdoch, called The Man Who Owns the News, published in 2008.
Murdoch, who spent more than 50 hours being interviewed by Wolff, was reported to have been frustrated with some elements of his portrayal.
Other criticism of his reporting has also emerged. A profile of Wolff in the New Republic magazine in 2004 questioned the way he retold events in his columns.
"The scenes in his columns aren't recreated so much as created - springing from Wolff's imagination, rather than from actual knowledge of events," it read.
"Even Wolff acknowledges that conventional reporting isn't his bag. Rather he absorbs the atmosphere and gossip swirling around him at cocktail parties, on the street, and especially during those long lunches."
His approach to the Trump book, based on more than 200 interviews, has also sparked criticism in some quarters.
A note explaining his sources for the book attached to an extract published in the New York Magazine described an unconventional approach.
"Sources would fail to set any parameters on the use of a conversation, or would provide accounts in confidence, only to subsequently share their views widely."
The note said the "Trumpian" approach to sharing information from advisers provided a "hodgepodge of journalistic challenges" for the book.
Some quoted in the book have since publicly criticised the characterisation of conversations.
The White House has insisted that Trump did not give Wolff an interview specifically for the book.
In turn, Wolff said they talked for three hours, but admitted Trump may not have "realised" it was for the publication.
Wolff's book also suggested Trump did not know former Republican House speaker John Boehner - though it has since emerged the pair were golfing partners before he entered the White House.
On his approach to stories heard in the White House, Wolff wrote: "Many of the accounts of what has happened in the Trump White House are in conflict with one another; many, in Trumpian fashion, are baldly untrue.
"Those conflicts, and that looseness with the truth, if not with reality itself, are an elemental thread of this book."
Other reporters have defended the revelations in the book.
Mike Allen, the co-founder of websites Politico and Axios, who is known for his contacts, gave some support last Friday
"In the past year we have had many of the same conversations with the same sources Wolff used," Allen wrote in his morning briefing email for Axios.
"We won't betray them, or put on the record what was off. But, we can say that… [some] lines from the book ring unambiguously true."
Wolff, whose book has turned him into one of the most famous journalists in America, is sticking to his story.
He says he has notes and recordings of some conversations - though declined to publish them when prompted in an interview on Friday.
"I've written many books, I've written millions upon millions of words.
"I don't think there has ever been one correction," he told NBC News.
He added: "I am certainly and absolutely in every way comfortable with everything I've reported in this book."