The real mystery is what the reader is supposed to make of Beyond the Rock. A biography, a cultural analysis, a true-crime investigation; each of these would be worthy of a book on its own. McCulloch throws them all in the mix, a sort of three-for-one deal; unfortunately none receive the treatment they deserve here. The biographical sections are treated conventionally and chronologically, and while McCulloch hints at bisexuality and marital woes, she retreats from these speculations just as quickly, leading one to suspect she either lacks the courage of her convictions or she simply does not know either way. Any exploration of the impact of the film adaption, which cemented the story in the public imagination, is reduced to little more than a series of anecdotes about unexplained happenings and other difficulties that interrupted production.

The crux of both books is the true crime angle. For every reminder that Picnic at Hanging Rock is a work of fiction, McCulloch insists it hides a chilling riddle yet to be solved. Only it doesn't. She blithely glosses over the existence of the final chapter penned by Lindsay (and withheld from publication until 1987), which provides a mystical resolution to the novel. And the revelation that Lindsay may have drawn inspiration from other artworks or events is not nearly as mysterious as McCulloch makes out. She includes vague references to bloodthirsty bushrangers in the Macedon area and relies heavily on a report of an excursion to Hanging Rock in 1919 from nearby Clyde School – whose Melbourne campus Lindsay attended several years earlier – even though there is no suggestion that anything especially untoward occurred on that occasion, at least on the evidence McCulloch presents. Then, as if to chastise the reader for expecting more from her, she resorts to stating that nobody knows (anything) for sure, and “a little mystery is a wonderful thing”. In fact, McCulloch spins this out until the very last paragraph of her Afterword, then introduces the astonishing claim that she has a file of material to support her theory, which may be published at some future date. What, then, was the point of the previous 198 pages?

McCulloch and her publishers have produced an undeniably handsome book, wherein her light and undemanding style reads like an extended feature article. However, as she takes great pains early on to establish herself as an investigative journalist of merit – devoting "five long years" to this project – the question should be asked: beyond the promises of rigorous research, pretty photographs and decorative motifs, where is the substance?

If you want a genuine insight into Joan Lindsay herself, better seek out a copy of either of her autobiographies, Time Without Clocks, or Facts Soft and Hard. And if you truly want to experience the mystery of Picnic at Hanging Rock, read the novel or watch the DVD.