The book was to focus on Lewandowski's tenure as campaign manager. Its tentative title was "Let Trump Be Trump."
Citing "two sources familiar with the talks," Politico reports that the publisher withdrew its offer after Lewandowski declined to show them the nondisclosure agreement he signed before joining Trump's campaign.
The nondisclosure agreement has been an issue with Lewandowski's role at CNN. "[I]t's something Trump uses to make someone like Lewandowski think twice before saying something bad about him," Callum Borchers wrote at the Washington Post.
That is, if Lewandowski's nondisclosure agreement – which he hasn't shared – is the same as the one the Associated Press obtained that other Trump employees had been required to sign.
That agreement, which is binding both during and after an employee's time working for Trump, makes them promise "not to demean or disparage" Trump, his family, or any of his companies, and prohibits those working for the candidate from disclosing information "of a private, proprietary or confidential nature or that Mr. Trump insists remain private or confidential."
One of Politico's publishing sources expressed shock over the $1.2 million HarperCollins had been willing to pay Lewandowski. "That's a huge figure for a political consultant who was fired before his biggest race was even over, and who has never won a major race before," the source said.
Lewandowski denied to Politico that he was trying to sell a book about the Trump campaign. "I'm not shopping a book deal," he said. "There is no contract for me. I have never seen it."
On Wednesday, Lewandowski reiterated his denial on Twitter, writing, "Once again @politico has their facts wrong and attributed to unnamed sources. Guess journalistic integrity doesn't rank as a priority there."
Yet as far back as May, BuzzFeed News reported that Lewandowski was writing an "insider's account" of his time working for the presumptive Republican presidential nominee.
Lewandowski was still employed by the Trump campaign at the time, and said the story was "100% not true."
Politico reports that Lewandowski abandoned his book plans after that, but revived them after he was fired.
Lewandowski was a source of controversy during his tenure with Trump's campaign. In March, he was charged with misdemeanor battery by prosecutors in Florida after news reporter Michelle Fields claimed he grabbed her roughly at a news conference, something that Lewandowski denied but was caught on video. County officials later dropped the charge, saying they didn't think it was likely they could successfully prosecute Lewandowski for the incident.
Lewandowski lost his job two months later in what was seen as a move by the Trump team to quell internal dissent in the campaign and create a smoother path to the White House.
HarperCollins is owned by News Corp, a media company founded by Rupert Murdoch. Murdoch and Trump have had a sometimes contentious relationship, but New York magazine has reported that the Australian media mogul plans to back Trump against Hillary Clinton in this year's presidential election.
The day after voters in the United Kingdom voted to leave the European Union, Trump and Murdoch, who both supported the "Brexit," had dinner together in Scotland.