Michael Wolff, the author of the new book “Fire and Fury: Inside the Trump White House,” extracts from which set the Internet ablaze on Wednesday, is an experienced magazine journalist. Among the publications on his résumé are New York, Vanity Fair, and the Hollywood Reporter. A chronicler of media, power, and wealth, Wolff is also willing to dish the dirt, as he demonstrated in a gossipy tome about Rupert Murdoch, which was published in 2008. After that book came out, there was an inquest inside Murdoch’s News Corporation into who had granted Wolff access. Fingers were pointed at Gary Ginsberg, a former Clinton Administration official who served for years as Murdoch’s political adviser, confidant, and fixer. Ginsberg subsequently left his job, and now works at Time Warner. But, as Wolff noted in a foreword to the paperback edition of the book, Murdoch was the person primarily responsible for the access he gained. The press baron “not only was (mostly) a patient and convivial interviewee but also opened every door I asked him to open,” Wolff wrote.

If there was a similar inquest at 1600 Pennsylvania Avenue about Wolff’s new book, it didn’t take long to identify a culprit. On Wednesday afternoon, the White House press office put out a statement in Trump’s name. “Steve Bannon has nothing to do with me or my Presidency,” it said. “When he was fired, he not only lost his job, he lost his mind. . . . Steve pretends to be at war with the media, which he calls the opposition party, yet he spent his time at the White House leaking false information to the media to make himself seem far more important than he was. It is the only thing he does well.” The statement goes on,“Steve was rarely in a one-on-one meeting with me and only pretends to have had influence to fool a few people with no access and no clue, whom he helped write phony books.”

The reason for Trump’s animus was obvious. “Fire and Fury” quotes Bannon, Trump’s former senior political adviser, as having described the June, 2016, meeting at Trump Tower between Donald Trump, Jr., Jared Kushner, Paul Manafort, and a group of people connected to Russia as “treasonous” and “unpatriotic,” and as saying that the meeting should have been reported to the F.B.I. The book contains myriad other damning comments about Trump and his family from Bannon and other Trump advisers.

There can be no doubt that Wolff relied on Bannon heavily. The book, a copy of which I obtained from the publisher, Henry Holt, on Wednesday, starts with the rumpled former investment banker having dinner with Roger Ailes, the late head of Fox News, in early January, 2017, and ends with Bannon standing outside the headquarters of Breitbart, the conservative news organization to which he returned after being ousted from the White House, in August. In the index, Bannon’s entry is considerably longer than anybody else’s except Trump’s.

Bannon wasn’t Wolff’s only source, though. The book is based on “conversations that took place over a period of eighteen months with the president, with most members of his senior staff—some of whom talked to me dozens of times—and with many people who they in turn spoke to,” Wolff writes in the author’s note. His original idea, he says, was to write a fly-on-the-wall account of Trump’s first hundred days. “The president himself encouraged this idea. But given the many fiefdoms in the White House that came into open conflict from the first days of the administration, there seemed no one person able to make this happen. Equally, there was no one to say ‘Go away.’ Hence I became more a constant interloper than an invited guest.”

Wolff’s methods will doubtless attract more scrutiny. In some places, he re-creates entire scenes, complete with dialogue, without explicitly identifying his sources. In others, he attributes withering comments about Trump to some of his current and former aides: “For Steve Mnuchin and Reince Priebus, the president was an ‘idiot.’ For Gary Cohn, he was ‘dumb as shit.’ For H.R. McMaster he was a ‘dope.’ The list went on.” On Wednesday, two people quoted in the book, Tom Barrack, a longtime friend of Trump, and Katie Walsh, a former White House aide, denied having made the negative comments about Trump that Wolff attributed to them. “We know the book has a lot of things, so far that we’ve seen, that are completely untrue,” the White House press secretary, Sarah Huckabee Sanders, said.

Still, the over-all portrait that Wolff draws of a dysfunctional, bitterly divided White House in the first six months of Trump’s Presidency, before the appointment of John Kelly as chief of staff and the subsequent firing of Bannon, has the whiff of authenticity about it—and it echoes news coverage at the time. Other details are impossible to confirm but damning if true. Such was the animosity between Bannon and “Jarvanka”—Bannon’s dismissive term for Ivanka Trump and Jared Kushner—Wolff reports, that, during one Oval Office meeting, Bannon called Ivanka “a fucking liar,” to which Trump responded,“I told you this is a tough town, baby.” Wolff also quotes Bannon commenting gleefully after Trump decided to pull the United States out of the Paris climate agreement, a decision that Ivanka opposed: “Score. The bitch is dead.”

Equally plausible is Wolff’s portrait of Trump as a one-dimensional figure who had no conception that he could win the 2016 election; little clue what to do after he did emerge victorious from the campaign trail; and virtually no interest in, or aptitude for, acquiring the skills and information needed to fulfill the role of President. “Here was, arguably, the central issue of the Trump presidency,” Wolff writes. The Commander-in-Chief “didn’t process information in any conventional sense—or, in a way, he didn’t process it at all.” He continues,

Trump didn’t read. He didn’t really even skim. If it was print, it might as well not exist. Some believed that for all practical purposes he was no more than semiliterate . . . . Some thought him dyslexic; certainly his comprehension was limited. Others concluded that he didn’t read because he didn’t have to, and that in fact this was one of his key attributes as a populist. He was postliterate—total television.