Historian Jenny Hocking has says the extent to which former governor-general Sir John Kerr continually wrote to the Queen, informing her of Australian political matters was "startling" and some of the communication was "scandalous".
It was Professor Hocking's years of persistence and legal challenges all the way to the High Court, which decided last month that the documents should be considered Commonwealth records and released by the National Archives of Australia.
"These are not appropriate conversations to be having between the governor-general and a member of the royal family, and it's very concerning that those conversations were had and that the Queen engaged and then further," Professor Hocking said.
The Monash University professor has written two biographies of former prime minister Gough Whitlam, and an account of the dismissal on November 11, 1975.
Professor Hocking said the letters were mainly as she expected, but she would be taking more time to fully explore their contents and implications. She said the letters showed concerning correspondence from the Queen's private secretary Sir Martin Charteris to Sir John about the use of reserve powers.
"I am surprised there was any discussion about reserve powers, that seems to be improper in that context," she said.
Reserve powers are those held by the governor-general to act without ministerial advice or even contrary to ministerial advice and include the power to dismiss a prime minister.
Professor Hocking said the volume of correspondence, as well as its detail about the political tensions and goings-on of the time, were not appropriate.
"The thing that has surprised me most in recent months as that came out of the court case, it was the number of letters, the fact there are over 200 letters and 1200 pages, is really extraordinary," she said.
"Normally a governor-general would be reporting to the palace, maybe only every year, maybe quarterly, to be sending this number of letters, does show that very close interaction between the palace and the governor-general at that time, over matters that were intensely and profoundly political."
Professor Hocking said she felt relief and delight that the letters had finally been released.
"It was always going to be one of the most important, if not the most important, holdings of archival material about the dismissal that we were ever likely to see, so the fact that we can now see it 45 years after the letters were written is really a wonderful moment for our history."