Mary Trump: Why has president's niece penned damning memoir?

US President Donald Trump's niece is set to publish an unflattering tell-all memoir about him. So who is she and why has she come forward now?

On 28 July, Mary Trump is due to release Too Much And Never Enough: How My Family Created the World's Most Dangerous Man, Simon & Schuster announced on Monday.

The book will hit the shelves just weeks before the Republican National Convention, when her uncle will accept the party's nomination for his re-election bid in November.

The memoir will reportedly reveal how she supplied the New York Times with confidential documents to print a sprawling investigation into Mr Trump's personal finances.

The Pulitzer Prize-winning exclusive alleged the president had been involved in "fraudulent" tax schemes and received more than $400m (£316m) in today's money from his father's real estate empire.

An Amazon blurb for the book says the author will set out how her uncle "became the man who now threatens the world's health, economic security and social fabric".

"She explains how specific events and general family patterns created the damaged man who currently occupies the Oval Office, including the strange and harmful relationship between Fred Trump and his two oldest sons, Fred Jr and Donald," it continues.

The blurb says the author will draw on her insights as a "firsthand witness to countless holiday meals and family interactions".

The memoir will also accuse the president of having "dismissed and derided" his father once he began to suffer from Alzheimer's.

Mary Trump, 55, is the daughter of Fred Trump Jr, the president's older brother, who died in 1981 at the age of 42.

He struggled with alcoholism for much of his life and his premature death was caused by a heart attack linked to his drinking.

President Trump has cited his brother's personal problems as spurring his administration's push for tackling the scourge of opioid addiction.

In an interview last year with the Washington Post, Mr Trump said he regretted pressuring his older brother to join the family real estate business as he pursued dreams of becoming a pilot.

Mary Trump has largely avoided the limelight since her uncle became president, though she has been critical of him in the past.

The bad blood between them goes back at least 20 years to a lawsuit filed by her and her brother against their uncle and his siblings.

In 2000, Mary Trump and Fred Trump III sued to dispute the money left to them by the estate of Donald Trump's father, Fred Trump Sr.

They said the 1991 will was "procured by fraud and undue influence" on the part of Donald Trump and his siblings, as the family patriarch suffered dementia, according to the New York Daily News.

Mary Trump told the city tabloid that her aunt and uncles "should be ashamed of themselves" over the legal battle.

"Given this family, it would be utterly naive to say it has nothing to do with money," she told the newspaper at the time.

Mary Trump and her brother filed another lawsuit after their medical insurance provided by the Trump company was cancelled in apparent retaliation for the first legal action.

The case was eventually settled and details were not released, reports say.

According to People magazine, public records show she was born Mary Lea Trump in May 1965 and lives on Long Island, New York.

Forbes magazine reports she earned a bachelor's in English Literature from Tufts University in Massachusetts and a master's in the same subject from Columbia University in New York.

She also did a PhD in clinical psychology at Adelphi University in New York.

According to a now-deleted LinkedIn profile, Mary Trump is a certified professional life coach.

In 2012, she reportedly founded a New-York based company, the Trump Coaching Group. 

Its website says: "Are you depressed and feeling low? Finding the true meaning of your life? If yes then our life coaches can bring you out from such dwindling situations."

According to tweets attributed to her, Mary Trump appears to have been feeling low on the day of her uncle's 2016 election.

An account bearing her name has a post that says: "This is one of the worst nights of my life."

Another tweet called the president's defeated rival, Hillary Clinton, "an extraordinary human being and public servant". 

The Twitter account's bio contains the Black Lives Matter hashtag, a gay pride flag and the pronouns she/her/hers.