A New York judge has temporarily blocked the publication of Mary Trump's scathing book about her uncle, President Donald Trump, which describes him as the "world's most dangerous man", saying no copies can be distributed until he hears arguments in the case.
The order leaves it uncertain whether the book will be published as scheduled on July 28.
Judge Hal Greenwald ordered a hearing next month on a request for an injunction by Mr Trump's brother Robert, who has argued that Mary Trump is not allowed to publish anything about her family as part of a settlement in an inheritance case.
His attorney, Charles Harder, said in a statement on Tuesday that he would seek the "maximum remedies available" for the "truly reprehensible" actions of Mary Trump and her publisher, which he said have caused "enormous damages" to his client.
"Short of corrective action to immediately cease their egregious conduct, we will pursue this case to the very end," Mr Harder said.
Mary Trump's attorney, Theodore Boutrous Jr, said in a statement that while the judge's order is temporary, "it still is a prior restraint on core political speech that flatly violates the First Amendment".
"We will immediately appeal. This book, which addresses matters of great public concern and importance about a sitting president in an election year, should not be suppressed even for one day."
Simon & Schuster said it also plans to appeal, adding in a statement that it looks forward "to prevailing in this case based on well-established precedents regarding prior restraint".
The book, titled 'Too Much and Never Enough: How My Family Created the World's Most Dangerous Man', has already ascended to the top of bestseller lists based on pre-sales, underscoring the intense interest in a rare insider account by a member of the Trump family.
In promotional material for the book, the publisher said Mary Trump "shines a bright light on the dark history of their family in order to explain how her uncle became the man who now threatens the world's health, economic security, and social fabric."
Simon & Schuster said in a filing late on Tuesday night that it had already printed 75,000 copies and argued that it would be unconstitutional to stop it from distributing the book.
At the same time, the publisher for the first time said that it did not know until recently that Mary Trump had signed a non-disclosure agreement as part of the inheritance settlement.
"We did not learn anything about Ms Trump signing any agreement concerning her ability to speak about her litigation with her family until shortly after press broke concerning Ms Trump's book about two weeks ago, well after the book had been accepted, put into production, and printing had begun," Simon & Schuster CEO Jonathan Karp said in an affidavit filed on Tuesday night.
"And we never saw any purported agreement until this action was filed against Ms Trump and Simon & Schuster."
While it has long been known that the inheritance case was settled confidentially, the terms of that agreement were not made public until Robert Trump filed his petition last week to stop publication the book.
Mr Karp in his affidavit also confirmed that Mary Trump was the "primary source" for an investigation by the 'New York Times' into the Trump family finances, which won the 2018 Pulitzer Prize, as the 'Daily Beast' first reported.
Mr Karp said that "knowing that no litigation resulted from the 'Times' article, we were entirely confident in Ms Trump's ability to tell her story regarding her own family".
Mr Karp said that even though the publication date is set for July 28, it may be too late to stop revelations in the book from being reported.
He said that "thousands" of the printed copies "have already been shipped".
Using her background as a clinical psychologist, Mary Trump explores the "nightmare of traumas" within the Trump family in the book, according to the publisher. (© Washington Post)