Mr Beazley, a former Australian ambassador to Washington, told Fairfax that the Wolff book is "internationally very damaging for the US; there is a lot of scepticism about Trump anyway, but ??? there is a sense that he has basically taken leave of his senses and is fundamentally out of control".

At a time when the US is running a "hard line" with South Korea and China on trade, risking a trade war, the book would "add to an impression around Trump of indiscipline, madness and miscalculation".

Mr Beazley added that the US leader seemed to have become convinced that the only way to disarm North Korean dictator Kim Jong-un was to "hit hard" but that Mr Trump has "no real understanding of what he is handling; and the book points out his deep ignorance and determination to [stay that way]".

"Trump really is prepared to go to war," Mr Beazley said, adding that both Secretary of State Rex Tillerson and US Defense Secretary Jim Mattis??? were against such a course and wanted time for tougher sanctions to bite.

Other international relations experts say the Wolff book is only likely to confirm what informed Washington-watchers already know. Professor Michael Wesley, Dean of the Australian National University's College of Asia and the Pacific, said he had not yet read the instant best-seller, replete with tales of dysfunction from inside the White House, but "from what I have read in terms of excerpts ??? I can't really see where the big surprise is".

"I think both allies and opponents are still trying to work out how to deal with this administration and this President, and I'm not sure a close reading of this book would really give a foreign policy-maker terribly much insight as to what to do about this guy," he told Fairfax Media.

He said Australia's diplomats and intelligence agencies were "already fairly avid readers of insider Washington stories, my understanding is that the absolute number one priority for the Australian embassy in Washington has been trying to get a read on Trump and his personality and how that interacts with the structures of American government."

But Professor Wesley warned the world was going to remain a more nervous place for the remainder of the Trump term. "When you look at the fact that he is starting to ramp up rhetoric on Iran, if you read his national security statement of December [with its tough talk on China and Russia] there is no question in my mind that he has started to think about who his next major enemy is going to be ??? the likelihood of a significant war happening with the US involved is a pretty serious one."

The head of the United States Studies Centre at Sydney University, Simon Jackman, said Fire and Fury would bring questions of Donald Trump's fitness and temperament "fundamentally back to centre-stage".

He said it was "remarkable to have a sitting US President tweeting that he is very smart and a genius and a stable one at that ??? But there is nothing in the US Constitution or on the law books that says the President has to have the kind of conventional empathy, magnanimity and grace that we have come to expect of presidents in the twentieth century [Nixon excepted]."

Professor Jackman said book would have less impact on Republicans than what might emerge from special counsel Robert Mueller's probe into Russian interference in the 2016 US presidential campaign. That, he said, was the "huge X-factor" in Washington for 2018.