Author Tony Schwartz, who confessed to writing all of Trump’s 1987 New York Times bestseller in a July New Yorker piece, on Wednesday discussed the reasons for his recent reveal and the subsequent letter he got from Trump’s attorneys in a MSNBC Rachel Maddow interview.

“It’s nuts and completely indicative of who he is,” Schwartz said of the letter. “There’s no basis in anything legal. I suspect Donald Trump called up his chief legal person and said, ‘Go after that guy and do whatever you have to do.'”

Schwartz already was listed as a co-author of Trump’s famous tome – the book the billionaire claims only comes second to the Bible in terms of its cultural significance – but now he admits Trump didn’t write a single page.

“I am not certain that Donald Trump read every word, but I’m sure certain that I wrote every word,” he told Maddow and Brian Williams. “He made a few marks in the manuscript and sent it back to me and the rest is history.”

In his cease and desist letter, Trump demanded Schwartz return all the royalties he received for the book, which he wrote after shadowing Trump for more than a year. Schwartz admitted he never felt the need to take full credit for the book until Trump’s bid for the highest office in the land became a real possibility.

“The idea that (Trump) would dispute that is part of why I felt I had to come forward,” Schwartz said. “If he could lie about that, Rachel, he could lie about anything.”