Inside Barbara Bush's Diaries: Her Disdain for President Trump and Soft Spot for Melania

According to her personal diaries, Barbara Bush's contempt for the current president dated back decades.

You would not have wanted to double-cross Barbara Bush, according to a new book.

Biographer Susan Page got exclusive access to the former first lady's personal diaries and spent hours interviewing her for her new biography, "The Matriarch: Barbara Bush and the Making of an American Dynasty."

“She was fierce, formidable, underestimated,” Page described Barbara. 

And she made no secret of her disdain for Donald Trump even before he became president.

“In 1990, she writes in her diary about the Trumps' divorce, about Donald's divorce from Ivanna, and says they are a symbol of the greed of the 1980s,” Page said. 

Page also says that Barbara was upset with Trump about how he treated her son, Jeb, on the campaign trail by calling him “Low-energy Jeb.” 

“She blamed [Trump] for her heart attack,” Page said. “She had a health crisis in June of 2016 that put her in the hospital and she thought it was because she was so anguished about Trump's campaign.” 

But Barbara had a soft spot for first lady Melania Trump. 

She wrote her a kind letter after the election, saying, “You're gonna love the White House, do what you want to do. Let me give you one piece of advice, think about having Barron have a friend with him because the White House can be a lonely place for a child.” 

Wednesday marks the one-year anniversary of Barbara's death, and the current first lady was there at her funeral in the front row.

The book makes a surprising revelation about Barbara and Nancy Reagan, with Page claiming “they had the worst relationship imaginable.” 

Reagan refused to invite the Bushes to their most famous White House party when they hosted Princess Diana and Prince Charles.

“The social secretary called her and said you can’t not invite the Bushes, he was the vice president! And she said, ‘just watch me,’” Page claimed. 

Click here to read an excerpt from "The Matriarch."