New York (AFP) - Donald Trump's niece is set to publish a no-holds-barred memoir next month that "shines a bright light on the dark history" of the US president's family, her publisher says.
Mary Trump will release "Too Much and Never Enough: How My Family Created the World's Most Dangerous Man," on July 28, according to Simon & Schuster.
It marks the first time that a member of Trump's family will publish unflattering stories about the former real estate tycoon and reality TV star.
Mary Trump, 55, is the daughter of Fred Trump Jr, the president's older brother, who died in 1981 at age 42 due to complications from alcoholism.
The 240-page book will detail events she witnessed as a child while spending time at her grandparents' house in New York's Queens borough, where her uncle and his four siblings grew up.
"She describes a nightmare of traumas, destructive relationships, and a tragic combination of neglect and abuse," Simon & Schuster said in a blurb about the book.
Mary Trump, a clinical psychologist, will say that the president, despite being his father's favorite son, "dismissed and derided him" when he began to suffer from Alzheimer's.
In the book, she explains "how specific events and general family patterns created the damaged man who currently occupies the Oval Office," the publisher said.
It will include "the strange and harmful relationship between Fred Trump and his two oldest sons, Fred Jr. and Donald," the blurb adds. Fred Trump died in 1999.
"She alone can recount this fascinating, unnerving saga, not just because of her insider's perspective but also because she is the only Trump willing to tell the truth about one of the world's most powerful and dysfunctional families," it concludes.
The book was first revealed by the Daily Beast on Sunday.
The website reported that Mary Trump will reveal that she was the primary source for the New York Times' Pulitzer Prize-winning investigation into Donald Trump's finances and taxes.
The investigation alleged that the president had received more than $400 million in today's terms from his father's real estate empire, much of it through fraudulent tax schemes.
A spokeswoman for The New York Times declined to comment in the newspaper's own article on the Daily Beast's claim that Mary Trump provided them with documents.
Several Trump aides and journalists have written books critical of the president, but Mary Trump's is billed as the first by a family insider.
The book is due out a few weeks before the Republican convention in August, when Trump will accept the party's nomination for his re-election bid in November.