She writes that Trump's father, Fred Trump, "dismantled his oldest son," Trump's brother, Freddy Trump.

"The only reason Donald escaped the same fate is that his personality served his father's purpose.

During the campaign, Mary Trump says her aunt, former federal judge Maryanne Trump Barry, accused Donald Trump of using Freddy Trump's death "for political purposes" by citing it while addressing the opioids crisis.

Mary Trump also claims that Donald Trump helped his sister to obtain an open seat in the US District Court for the District of New Jersey, through his friend and lawyer, Roy Cohn.

"Maryanne thought it would be a great fit, and Donald thought it might be useful to have a close relative on the bench in a state in which he planned to do a lot of business," she writes.

This came after Freddy left the Trump company, a move that angered Fred but which Freddy apparently hoped would ingratiate himself to his demanding father.

The stormy relationship she describes between Fred and Freddy Trump seem to echo accounts of how Donald, Freddy's younger brother, expects undying loyalty from those around him and seeks control over those people's lives and decisions.

Freddy, Mary writes, would tell friends about the "constant barrage of abuse" he was receiving from his father after getting the job at TWA.

"Donald may not have understood the origin of their father's contempt for Freddy and his decision to become a professional pilot, but he had the bull's unerring instinct for finding the most effective way to undermine an adversary," Mary Trump writes.

It was during this time that Freddy's drinking worsened, and within a few months he had quit the job at TWA, moved his family back to New York, and tried flying for smaller airlines.

The way Mary describes it, Fred's torment, with an assist from Donald, had "slowly, inexorably dismantled" Freddy.

'Master of the universe'

Mary Trump recounts the President's rise to prominence in New York real estate as largely the result of Fred Trump's financial and behind-the-scenes support, which she said was necessary to compensate for Donald's shortcomings.

She also traces what she views as an aptitude toward authoritarians to Donald Trump's earlier days working with famed lawyer Roy Cohn in the 1980s.

At the same time, she recounts Trump's apparent disinterest at her father's decline into depression and alcoholism, which she characterizes as spurred partly by her grandfather's decision to elevate Donald instead of Freddy as his right-hand man and successor.

Throughout, Mary Trump portrays the support Donald received from his father as critical to his attempts to create a brand for himself as a "master of the universe" with a preternatural ability for business.

"His comfort with portraying that image, along with his father's favor and the material security his father's wealth afforded him, gave him the unearned confidence to pull off what even at the beginning was a charade: selling himself not just as a rich playboy but as a brilliant, self-made businessman," she writes.