Its unresolved conclusion has sparked significant public, critical, and scholarly analysis, and the narrative has become a part of Australia's national folklore as a result.

Lindsay claimed to have written the novel over two weeks at her home Mulberry Hill in Baxter, on Victoria's Mornington Peninsula, after having successive dreams of the narrated events.

Miranda, Marion, and Irma climb still higher in a trance-like state while Edith flees in terror; she returns to the picnic in hysterics, disoriented and with no memory of what occurred.

The disappearances provoke much local concern and international sensation with rape, abduction, and murder being assumed as probable explanations.

Mike Fitzhubert, an Englishman who was picnicking at the grounds the same day, embarks on a private search of the rock and discovers Irma, unconscious and on the verge of death.

When he fails to return from his search, he is found in an unexplained daze, sitting at the rock with Irma, by his friend and uncle's coachman, Albert Crundall.

In a pseudo-historical afterword purportedly extracted from a 1913 Melbourne newspaper article, it is written that both the college and the Woodend Police Station, where records of the investigation were kept, were destroyed by a bush fire in the summer of 1901.

In 1903, rabbit hunters came across a lone piece of frilled calico at the rock, believed to have been part of the dress of the governess, Miss Greta McCraw, but neither she nor the girls were ever found.

According to her editor Sandra Forbes, Lindsay's original draft of the novel included a final chapter in which the mystery was resolved.

The missing material amounts to about 12 pages; the remainder of the publication The Secret at Hanging Rock contains discussion by other authors, including John Taylor and Yvonne Rousseau.

In a 2017 article in The Age, it was noted: "The dream had centred on a summer picnic at a place called Hanging Rock, which Joan knew well from her childhood holidays.

Joan told Rae [her housekeeper] that the dream had felt so real that when she awoke at 7.30am, she could still feel the hot summer breeze blowing through the gum trees and she could still hear the peals of laughter and conversation of the people she'd imagined, and their gaiety and lightness of spirit as they set out on their joyful picnic expedition.

[8][14] However, while the geological feature, Hanging Rock, and the several towns mentioned are actual places near Mount Macedon, the story itself is entirely fictitious.

[15][16] Lindsay had done little to dispel the myth that the story is based on truth, in many interviews either refusing to confirm it was entirely fiction,[17] or hinting that parts of the book were fictitious and that others were not.

For instance, Valentine's Day, 14 February 1900, occurred on a Wednesday, not a Saturday; similarly, Easter Sunday fell on 15 April in 1900, not on 29 March.

[18] Appleyard College was to some extent based on Clyde Girls' Grammar School at St Kilda East, Victoria, which Joan Lindsay attended as a day-girl while in her teens.

"[20] The unresolved mystery of the disappearances in the novel aroused so much lasting public interest that in 1980 a book of hypothetical solutions (by Yvonne Rousseau) was published, called The Murders at Hanging Rock.

[21] The novel was first published on 1 November 1967 by F. W. Cheshire, Melbourne, under the aegis of Andrew Fabinyi,[8] with an acclaimed "dream-like" cover design by Alison Forbes.

[27] Much of the critical and scholarly interest in the novel has centred on its mysterious conclusion, as well as its depiction of Australia's natural environment in contrast with the Victorian population of the British colony established in 1851.

"[29] Literary scholar Kathleen Steele argues in her essay "Fear and Loathing in the Australian Bush: Gothic Landscapes in Bush Studies and Picnic at Hanging Rock" that the novel's treatment of landscape and its missing characters is reflective of Australia's national history and the relationship between the rock and the Aboriginal population: "The silence surrounding Aborigines, and the manner in which Europeans foregrounded 'geographical, historical and cultural difference and discontinuity,' yet denied Aborigines either presence or history, created a gothic consciousness of 'something deeply unknowable and terrifying in the Australian landscape.'"

... "Lindsay provokes a reflection on the understanding of Australia as an un-peopled land where nothing of consequence occurred until the British gave it a history.

However, only about ten minutes of footage was filmed before the rights were optioned to Peter Weir for his more famous feature-length version, and the production was permanently shelved.

[31] The feature film version of Picnic at Hanging Rock premiered at the Hindley Cinema Complex in Adelaide on 8 August 1975.