 -- A day after Steve Bannon unceremoniously stepped down from Breitbart News, Michael Wolff, author of the politically-disruptive book on the Trump White House that publicized many of Bannon’s frustrations, claimed responsibility for the former chief strategist's ousting.

“It certainly wasn't something I expected," Wolff said on ABC's "The View" Wednesday. "It's certainly not something I feel good about,”

Bannon was a key source in Wolff’s book, "Fire and Fury: Inside the Trump White House," and offered sharp criticism of the president and others, including his adult children.

“Shortly after arriving in this White House, [Bannon] began to understand that … Trumpism and Donald Trump were at a significant distance from each other,” Wolff said. “I think Steve wrestled with that in very, very tough ways. Ultimately, I was the recipient of his enormous frustration.”

“So you're the reason he's out?” Joy Behar, one of the hosts on “The View,” asked.

“I'm the reason he's out,” Wolff responded.

But the tense White House dynamics went far beyond Bannon and the president, Wolff said. From his time sitting on a couch in the West Wing waiting for appointments with different members of the administration -- a position he said he got because he “slipped through the cracks” -- Wolff said he noticed three "factions."

One of the factions was "Jarvanke," the disparaging term Bannon sued for Jared and Ivanka Trump. The other competing ideas came from Bannon himself and former Chief of Staff Reince Priebus.

“They regarded -- each of these factions, the 'Jarvanka' side, the Bannon side and Priebus side -- regarded the others as assassins,” he said.

Wolff has been on the television circuit promoting the book and an explosive excerpt in New York Magazine since they were published. The book currently sits at No. 1 on the Amazon books best-sellers list.

He has faced a number of questions about his reporting in the wake of the salacious details that have emerged from the book, but has steadfastly stood by his work. White House officials have disputed his claim that he held "something like a semi-permanent seat on a couch in the West Wing," and have called the book "fiction."

Meghan McCain, co-anchor on “The View,” raised the credibility question to Wolff.

“Traditionally, in situations like this, it’s the disgruntled staffers who aren’t loyal to their principal that give interviews like this. So I’m curious, when you talk about staff, you didn’t talk to his cabinet? Did you ever interview Jared and Ivanka?” McCain asked.

She also expressed skepticism about the quotes attributed to Tony Blair, Tom Barrack, Kate Walsh, Anna Wintour, all of whom denied their quotes and attribution in the book.

“I think you have to look at the other people who aren't denying, a great number of people,” Wolff responded.

Last week, the book prompted a cease-and-desist letter from one of Trump’s lawyer. In the days following, the president released a Tweet-storm about the credibility of the book and the questions it raised over the president’s own mental stability.

Charles Harder, the Trump lawyer who called for the cease-and-desist, wrote that he was "investigating numerous false and/or baseless statements" about the president contained within the book. He also said it included defamatory statements and could be considered an "invasion of privacy."

In response Monday, a lawyer for Henry Holt & Company, which published the book, responded to Harder, saying there is "no reason to doubt...that Mr. Wolff's book is an accurate report on events of vital public importance" and that Harder's letter "provides no reason to change this conclusion."

"Though your letter provides a basic summary of New York libel law, tellingly, it stops short of identifying a single statement in the book that is factually false or defamatory," the letter, sent on Monday, read. "Instead, the letter appears to be designed to silence legitimate criticism. This is the antithesis of an actionable libel claim."

Henry Holt and Company moved up its original Jan. 9 publication date to last Friday and the book quickly became a best-seller.