In her new memoir, President Trump's niece reveals how she leaked hordes of confidential Trump family financial documents to the New York Times in an effort to expose her uncle, whom she portrays as a dangerous sociopath.

Why it matters: Trump was furious when he found out recently that Mary Trump, a trained psychologist, would be publishing a tell-all memoir. And Trump's younger brother, Robert, tried and failed to block the publication of "Too Much and Never Enough: How My Family Created the World's Most Dangerous Man."

• Axios obtained a copy ahead of the expected release later this month.

Behind the scenes: In what reads like a scene out of Spotlight, Mary Trump tells the story for the first time of how she secretly gave the New York Times much of the source material for its 14,000 word investigation of how "President Trump participated in dubious tax schemes during the 1990s, including instances of outright fraud, that greatly increased the fortune he received from his parents."

• Mary Trump writes that in the spring of 2017, her doorbell rang. "When I opened the door, the only thing that registered was that the woman standing there. with her shock of curly blond hair and dark-rimmed glasses, was someone I didn't know. Her khakis, button-down shirt, and messenger bag placed her out of Rockville Center."
• "Hi. My name is Susanne Craig. I'm a reporter for the New York Times."

Mary Trump says she initially turned Craig away, telling her that she didn't talk to reporters and it was "so not cool" that she was showing up at her house.

But Craig persisted, giving Trump her business card and later following up with a letter "reiterating her belief that I had documents that could help 'rewrite the history of the President of the United States,' as she put it."

• After a month of sitting on her couch, scrolling through Twitter, and growing increasingly agitated as "Donald shredded norms, endangered alliances, and trod upon the vulnerable," the president's niece picked up Craig's card and called her.
• What follows is one of the most vivid passages in the book. Mary Trump reveals how she smuggled a motherlode of financial documents out of the law firm, Farrell Fritz.
• "At 3:00, I drove to the loading dock beneath the building, and nineteen boxes were loaded into the back of the borrowed truck I was driving since I couldn't work the clutch in my own car."
• "It was just beginning to get dark when I pulled into my driveway. The three reporters [from the New York Times] were waiting for me in David's white SUV, which sported a pair of reindeer antlers and a huge red nose wired to the grill."
• "When I showed them the boxes, there were hugs all around. It was the happiest I'd felt in months."
• The president's niece goes on to recount conversations with the president's sister, who suspected other members of the family were guilty of leaking to the Times.

Mary Trump's bottom line: Her book is laced with guilt and her motivations appear to be to alleviate that feeling."It wasn't enough for me to volunteer at an organization helping Syrian refugees," she writes. "I had to take Donald down."

Editor's note: This is a developing story and will be updated.