If Bolton is to be believed, here are five memorable takeaways from "The Room Where It Happened: A White House Memoir" -- beyond the bombshell headlines published so far:
Trump obsessed about photo ops with North Korea's Kim, had special gift for him
He says at their first summit, through interpreters, Trump was extremely complimentary of Kim, saying he saw the dictator "as really smart, quite secretive, a very good person, totally sincere, with a great personality."
Corroborating previous reporting, Bolton writes Trump made it a priority on that trip for Secretary of State Mike Pompeo to deliver a special gift for Kim.
"Trump didn't seem to realize Pompeo hadn't actually seen Kim Jong Un, asking if Pompeo had handed over the Trump-autographed copy of Elton John's 'Rocket Man' CD, which Pompeo had not. Getting this CD to Kim remained a high priority for several months," Bolton writes.
Trump had mocked Kim for firing off missiles by calling him "Little Rocket Man," but wanted to persuade him that it was really a compliment, he writes.
Though Bolton didn't attend the third summit, in which Trump crossed into North Korea, the hawkish Republican says "the whole thing made me ill."
"Trump walked into North Korea, with Kushner and Ivanka nearby. Kim looked delighted in the pictures, as he should have. What an incredible gift Trump had given him, coming to the DMZ for the personal publicity," Bolton says.
Trump defended Saudi crown prince to distract from daughter Ivanka's use of personal email account
As allegations emerged that Saudi Crown Prince Mohammed bin Salman ordered the killing of Washington Post columnist Jamal Khashoggi, Bolton claims Trump sought to take advantage of the news to distract from a scandal involving his daughter.
"'This will divert from Ivanka,'" Bolton writes Trump said at the time. "'If I read the statement in person, that will take over the Ivanka thing.'"
Trump ultimately issued the statement, but did not read it.
"'Goddamn it, why didn't she change her phone? What a mess we have because of that phone,'" Trump said, Bolton adds.
Trump 'pleading' with China's Xi for reelection help included backing concentration camps
In the book, Bolton says that Trump's decision-making was driven by the 2020 election, and that included his interactions with foreign leaders.
"I am hard-pressed to identify any significant Trump decision during my tenure that wasn't driven by re-election calculations," he writes.
Bolton says at the same G-20 summit in Japan during which Trump asked President Xi Jinping to buy a large amount of U.S. agricultural products to help him win American farm states in November's election, he also endorsed mass concentration camps Beijing has used to imprison and "re-educate" Uyghurs and other Muslim ethnic minorities.
"He [Trump] then, stunningly, turned the conversation to the coming US presidential election, alluding to China's economic capability to affect the ongoing campaigns, pleading with Xi to ensure he'd win. He stressed the importance of farmers, and increased Chinese purchases of soybeans and wheat in the electoral outcome," Bolton writes.
On the sidelines of the event, Bolton writes that, "According to our interpreter, Trump said that Xi should go ahead with building the camps, which Trump thought was exactly the right thing to do. The National Security Council's top Asia staffer, Matthew Pottinger, told me that Trump said something very similar during his November 2017 trip to China."
"Religious repression in China was also not on Trump's agenda; whether it was the Catholic Church or Falun Gong, it didn't register," Bolton continues.
Bolton also says Trump also told Xi that Americans were eager for him to serve beyond two terms, despite being barred from doing so by the Constitution.
Trump has called Bolton a "liar" putting out "fake stories," and aides who say they were present at the G-20 summit deny Bolton's allegation that Trump asked Xi for reelection help.
Bolton blames his not testifying on Democrats, accusing them of 'impeachment malpractice'
The question on the minds of many -- and posed by ABC News' Chief Global Affairs Correspondent Martha Raddatz to Bolton in an exclusive interview airing Sunday -- is why Bolton didn't come forward sooner with his shocking allegations.
In the book, he blames House Democrats, calling their proceedings and charges filed against Trump a case of "impeachment malpractice."
"Had Democratic impeachment advocates not been so obsessed with their Ukraine blitzkrieg in 2019, had they taken the time to inquire more systematically about Trump's behavior across his entire foreign policy, the impeachment outcome might well have been different," he writes, detailing what he claimed are specific episodes of Trump excusing behavior by foreign mega-firms that was then under U.S. criminal investigation, including Halkbank in Turkey and ZTE in China.
He says the House should have looked into how President Trump regularly expressed willingness to intervene in criminal investigations "to, in effect, give personal favors to dictators he liked."
"The pattern looked like obstruction of justice as a way of life," writes Bolton.
House Speaker Nancy Pelosi and a wave of Democrats have complained since February that Bolton should come forward with his claims by testifying under oath before Congress.
"He chose loyalty over patriotism," she said Thursday.
Though Bolton offered to testify in the Senate trial, Republicans blocked the move.
Trump created toxic WH environment and aides mocked him behind his back
Bolton says that Trump created a toxic work environment in the White House West Wing, describing him as "erratic" and eager to indulge his "reality TV showmanship" at all costs -- and that even those in Trump's innermost circle "hold a dim view of him in private."
"He second-guessed people's motives, saw conspiracies behind rocks, and remained stunningly uninformed on how to run the White House, let alone the huge federal government," Bolton writes.
Bolton says that even Secretary of State Pompeo, considered a close Trump ally, during a 2018 meeting with Kim Jong Un slipped Bolton a note that said of the president, "He is so full of sh--."
Bolton also writes former White House Chief of Staff John Kelly also told him, "'This is a bad place to work, as you will find out.'"
Bolton also details incidents where he says he, Pompeo and Kelly mocked members of Trump's family, saying Pompeo at one point joked the administration could soon become "the Donald, Ivanka and Jared show."
In a statement issued late Thursday, with the headline "I Was In The Room Too," Pompeo said, "I’ve not read the book, but from the excerpts I’ve seen published, John Bolton is spreading a number of lies, fully-spun half-truths, and outright falsehoods. It is both sad and dangerous that John Bolton’s final public role is that of a traitor who damaged America by violating his sacred trust with its people."
Bolton's book is scheduled to be released next Tuesday, June 23.
Tune into "The Room Where It Happened: ABC News Exclusive Interview with John Bolton" –- The ABC News primetime special airs 9–10 p.m. ET, Sunday, June 21.
ABC News' Nadine Shubailat and Conor Finnegan contributed to this report.