What role did the queen play in Governor-General Sir John Kerr's plans to dismiss Prime Minister Gough Whitlam in 1975, unleashing one of the most divisive episodes in Australia's political history? And why weren't we told?

Under the cover of being designated as private correspondence, the letters between the queen and the governor-general about the dismissal have been locked away for decades in the National Archives of Australia, and embargoed by the queen - potentially forever. This ruse has furthered the fiction that the queen and the palace had no warning of or role in Kerr's actions.

In the face of this, Professor Jenny Hocking embarked on a four-year legal battle to force the Archives to release the letters. In 2015, she mounted a crowd-funded campaign, securing a stellar pro bono team that took her case all the way to the High Court of Australia.

Now, drawing on never-before-published material from Kerr's archives and her submissions to the court, Hocking traces the collusion and deception behind the dismissal, and charts the secret role of High Court judges; the leader of the opposition, Malcolm Fraser; and the queen's private secretary in fostering and supporting Kerr's actions.

Hocking also reveals the obstruction, intrigue, and duplicity she faced, raising disturbing questions about the role of the National Archives in preventing access to its own historical material and in enforcing royal secrecy over its documents.