Acclaimed journalist Bob Woodward’s upcoming new book, Fear: Trump in the White House, is set to provide a behind-the-scenes look at the distrust within the president’s inner circle and the chaos that reportedly consumes his White House.

According to excerpts obtained Tuesday by CNN and The Washington Post, Woodward’s book uses deep-background interviews with many Trump staffers to illustrate how Trump’s top advisers view him in a stunningly negative light and how the president’s obsession with the Russia probe has driven a wedge between him and his most trusted advisers.

In the book, Woodard says he conducted hundreds of hours of interviews with people who were participants and witnesses in the conversations he describes. The journalist also tapped notes, diaries, and government documents from these aides.

Here are the most eye-popping excerpts from the approximately 448-page book that is scheduled for release on September 11:

Trump Mocked Sessions’ Accent, Called Him ‘Mentally Retarded’

After learning Robert Mueller had been appointed special counsel last year, Trump went after his attorney general, calling him a “traitor” for recusing himself in the ongoing Russia probe.

Trump reportedly complained that “everyone was out to get” him, and while mocking Sessions’ accent, reportedly said to a staffer, “This guy is mentally retarded. He’s this dumb Southerner… He couldn’t even be a one-person country lawyer down in Alabama,” according to the excerpt obtained by The Washington Post.

White House Lawyer Wanted to Prevent ‘Idiot’ Trump from Testifying to Mueller

According to Woodward, Trump’s former personal lawyer, John Dowd, explained to Mueller why he wanted to prevent the president from testifying to the special counsel and his team:

“I’m not going to sit there and let him look like an idiot. And you publish that transcript, because everything leaks in Washington, and the guys overseas are going to say, ‘I told you he was an idiot. I told you he was a goddamn dumbbell. What are we dealing with this idiot for?’ ”

“John, I understand,” Mueller replied to Dowd, according to the book.

John Kelly Called Trump an ‘Idiot,’ Lamented ‘Worst Job I’ve Ever Had’

Chief of Staff John Kelly frequently lost his temper and told close aides that he thought Donald Trump was “unhinged,” Woodward writes in the new book.

The journalist details one meeting where Kelly allegedly lamented to colleagues about Trump: “He’s an idiot. It’s pointless to try to convince him of anything. He’s gone off the rails. We’re in crazytown. I don’t even know why any of us are here. This is the worst job I’ve ever had.”

Kelly later denied this claim in a statement issued Tuesday. “The idea I ever called the President an idiot is not true,” said Kelly. “As I stated back in May and I still firmly stand behind: ‘I spend more time with the President than anyone else, and we have an incredibly candid and strong relationship. He always knows where I stand, and he and I both know this story is total BS. I’m committed to the President, his agenda, and our country. This is another pathetic attempt to smear people close to President Trump and distract from the administration’s many successes.”

Mattis ‘Exasperated’ by Trump’s ‘Fifth-Grader’ Understanding of North Korea

Defense Secretary James Mattis bluntly complained of Trump’s understanding of Korea strategy as being that of an elementary school student.

In a meeting in January 2018, Mattis reportedly grew frustrated at the president’s dismissal of the significance of a U.S. military presence in the Korean Peninsula. In an excerpt obtained by The Washington Post, Trump questioned why the U.S. was using resources in the region at all.

“I think we could be so rich if we weren't stupid,” Trump later said in the meeting, with Woodward reporting the president later said the U.S. was being played as “suckers.”

“We’re doing this in order to prevent World War III,” Mattis explained to the president, according to Woodward.

After Trump left the meeting, Woodward writes, “Mattis was particularly exasperated and alarmed, telling close associates that the president acted like—and had the understanding of—‘a fifth- or sixth-grader.’”

In a statement Tuesday afternoon, Mattis claimed: “The contemptuous words about the President attributed to me in Woodward’s book were never uttered by me or in my presence.”

Cohn Stole Papers from Trump’s Desk to Prevent NAFTA Withdrawal

In an effort to curb the president’s “most dangerous impulses,” Trump’s former chief economic adviser Gary Cohn swiped multiple official documents from the president’s desk so he wouldn’t sign them, according to Woodward.

"I stole it off his desk," Cohn told an associate of a document withdrawing the U.S. from a crucial trade deal with South Korea, per the excerpts reviewed by CNN. "I wouldn't let him see it. He's never going to see that document. Got to protect the country.”

Cohn also allegedly removed from the Oval Office a notification letter to withdraw from the North American Free Trade Agreement (NAFTA), worried about the economic repercussions of pulling out.

Eager to withdraw from the international trade deal, Trump told former White House aid Rob Porter, “Why aren’t we getting this done? Do your job. It’s tap, tap, tap. You’re just tapping me along. I want to do this.”

When Porter consulted Cohn about the request, Cohn told him not to worry, allegedly replying: “I can stop this. I’ll just take the paper off his desk.”

Trump Ordered Mattis to ‘Fucking Kill’ Bashar al-Assad

Per The Washington Post’s summary of the excerpts: “After Syrian leader Bashar al-Assad launched a chemical attack on civilians in April 2017, Trump called Mattis and said he wanted to assassinate the dictator. ‘Let’s fucking kill him! Let’s go in. Let’s kill the fucking lot of them,’ Trump said, according to Woodward.”

Trump Called Obama a ‘Weak Dick’ for Not Acting in Syria

On a related note, according to the excerpts obtained by CNN, Trump told Sen. Lindsey Graham—a golfing buddy of his—that President Barack Obama was a “weak dick” for not taking more decisive action in Syria.

Ivanka Trump, a White House Staffer, Refuses to Be Treated as Staffer

According to the excerpts, White House adviser Ivanka Trump refused to follow normal staffer protocol because she is the president’s daughter.

“You’re a goddamn staffer!” former chief White House strategist Steve Bannon reportedly screamed at her, insisting she report to the chief of staff like all other aides. “You walk around this place and act like you’re in charge, and you’re not. You’re on staff!”

Her response, according to Woodward: “I’m not a staffer! I’ll never be a staffer. I’m the first daughter.”

Trump Personally Insults His Cabinet Members

According to the excerpts, Trump would often insult his top cabinet members, once reportedly mocking former national security adviser H.R. McMaster’s bravado and commenting on how he dressed in cheap suits, “like a beer salesman.”

In another excerpt, Trump allegedly told his Commerce Sec. Wilbur Ross, “I don’t trust you. I don’t want you doing any more negotiations… You’re past your prime.”

Trump Considers Himself the Ernest Hemingway of Twitter

The president is quite proud of his tweeting habits, according to the excerpts obtained by The Washington Post. But according to Woodward, staffers are often concerned his firebrand social-media persona could endanger American security. “Twitter could get us into a war,” one national-security leader reportedly feared. According to Woodward, Trump aides formed a committee to attempt to review Trump’s tweets, but failed.

Per the Post: “Priebus, who was blindsided when Trump announced his firing on Twitter, referred to the presidential bedroom as ‘the devil's workshop’ and called the early morning hours and Sunday night—a time of many news-breaking tweets—‘the witching hour.’”

And when Twitter expanded its character limit to 280, Trump—ever-so-pleased with his tweeting habits—reportedly said, “It’s a good thing, but it's a bit of a shame because I was the Ernest Hemingway of 140 characters."