It's one of the rarest, most mysterious, books in existence, and now the curators of the fabled Voynich manuscript are allowing copies to be made for the first time in the hope of cracking its secrets.
But if you do fancy your chances at decoding this 400-year-old tome, be warned that, up until now, no one has been able to - not even the Second World War cryptographers who smashed the Nazis' most difficult cyphers.
The manuscript came to light in 1912 and is named after Polish bookseller Wilfrid Voynich, who bought it among a job lot of books from the Collegio Romano in Italy.
Among its 240 pages are illustrations of plants and stars in the night sky, as well as a closely handwritten text that, if it is in a genuine language, isn't one for which any other record in the entire world remains.
The book is currently under lock and key at Yale University in the US, but Raymond Clemens, curator of the Beinecke Rare Book and Manuscript Library there, says an agreement has been reached with the small Spanish publishing house, Siloe, to produce 898 facsimile copies.
According to Siloe's website: "The Voynich manuscript is the only medieval text that remains to be decrypted on the planet.
"What language, writing system or cryptographic code is written? What led to this mysterious author to write a treatise intended apparently not be read by anyone?"
What, indeed? Naturally, conspiracy theories abound, from those who claim it's a hoax dating back no further than its discovery in 1912, to others who suggest it holds the key to extraterrestrial life.
And Siloe ramps up the enigma with its speculation: "It could be the prescription for a contraceptive potion or a secret alchemical formula for obtaining gold - the famous philosopher's stone, or perhaps an Elvish will. Or it could, as noted by others, hide the secret of immortality. Are we, perhaps, as has also been suggested, before the day of an alien?"
But, in plain English, what are the best guesses at what's actually in this mysterious document?
The manuscript is written on vellum that has been carbon-dated to the early 15th Century, and it's said to have once passed through the hands of Rudolf II, Emperor of the Habsburg Empire in Prague and collector of occult artefacts.
But the BBC's Simon Worrall wasn't convinced when he inspected it for Radio 4 two years ago, and wrote: "I believe the manuscript is a forgery by Wilfrid Voynich himself. One of the most common tropes in the history of forgery is that of a rare book dealer 'discovering' previously unknown manuscripts. Voynich is known to have had just this 'magic' touch.
"He is also said to have acquired a large supply of vellum and to have used his knowledge of chemistry gained at the University of Moscow to replicate medieval inks and pigments."
Google the words Voynich and aliens and you'll find any amount of bonkers-ness.
Here's one theory randomly lifted from ancient-code.com: "Because it contains a language that cannot be found anywhere else on the planet, and given the fact that the ancient manuscript depicts star charts that are unknown to us, the Voynich manuscript could have been created by a being not from Earth, who during the 1400s crash-landed on Earth and created the manuscript documenting life on earth.
"Knowing that humans did not possess the necessary technology to help the alien visitor return to his planet, it is possible the alien visitor decided to chronicle his remaining life on our planet inside the manuscript."
Stephen Bax, professor of modern languages and linguistics at the Open University, writes on his website - with an apology to conspiracy theorists - that he believes it to "probably to be an attempt at an encyclopaedia or 'summa' aiming to encompass contemporary knowledge of plants, astrology/astronomy and related areas."
There are some suggestions that the aforementioned Rudolf II bought the book for 600 gold ducats from Dr John Dee, a mystic and astrologer from the court of Elizabeth I, and his companion, Edward Kelley.
Kelley was a noted fraudster and died after falling from a tower where he'd been imprisoned by Rudolf for singularly failing to produce the gold he claimed he could create through alchemy.
Was the Voynich simply another Kelley scam?
Whatever the truth is, the public will soon be able to get their own hands on a copy ... albeit for a princely sum of £6,000.