The Daily Beast first reported on the forthcoming book, in which Mary Trump will detail how she was a primary source for the New York Times' Pulitzer-winning investigation into Donald Trump's "dubious tax schemes" during the 1990s.
The blockbuster investigation, published in October 2018, revealed that Trump "received the equivalent today of at least $413 million from his father's real estate empire, starting when he was a toddler and continuing to this day."
"Too Much and Never Enough" is said to include "intimate and damning" conversations between Mary Trump and Donald Trump's sister, retired federal judge Maryanne Trump Barry.
Although details about the tell-all book are being kept under wraps, Mary Trump will allege that President Trump and his father, Fred Sr., "contributed to" the death of her own father, Fred Jr., in 1981 at 42 years old after a long struggle with alcoholism.
In a description of "Too Much and Never Enough" posted on Amazon, Mary Trump is said to describe "a nightmare of traumas, destructive relationships, and a tragic combination of neglect and abuse."
Mary Trump and her brother, Fred III, notably sued other members of the Trump family in 2000, alleging that their relatives had persuaded Fred Trump Sr. to change his will and deprived them of what they believed was their father's fair share of the family wealth.
President Trump has since claimed that the financial feud with his late brother's children had been settled amicably, although details about the case have never been made public.
"Too Much and Never Enough" will be published a few weeks ahead of the 2020 Republican National Convention, which is scheduled to take place from August 24 to 27 in Jacksonville, Florida.
Although Mary Trump's book is said to include revelations that could be particularly damaging for President Trump, several former White House aides and Trump administration members have published equally explosive exposés in recent years.
Among them are the former F.B.I director James Comey, whose political memoir "A Higher Loyalty: Truth, Lies and Leadership" topped 600,000 copies during its first week at US bookshops.
Meanwhile, veteran reporter Bob Woodward's "Fear: Trump in the White House" sold more than a million copies in the first week of its release in the US, making it the fastest-selling opener in the history of publisher Simon & Schuster.