Incidentally, if you're familiar with the "Patterns" literature (where recurring patterns of behaviour are given names in order that people can recognize them and manage their causes, rather than simply fire-fighting their consequences), you should be very comfortable with the monomyth: it's basically a pattern template for mythological behaviours.
The first of Campbell's stages is the "Call To Adventure": someone (a Herald) or something (a Macguffin, say) challenges the Hero (and, behind the scenes, often the Anti-Hero too) to take temporary leave of his Ordinary World (DullWorld) to enter the Special World of the Macguffin (DangerWorld). Stage Two is where the Hero says: errrm, thanks... but no thanks, I'm actually quite happy here sweeping the floors [A.K.A. "Refusal of the Call"], while Stage Three is where the unseen writing Gods swoosh the Hero up like the miserable piece of snot he is and propel him onwards to his adventure in DangerWorld, whether he likes it or not [A.K.A. "Supernatural Aid"]. Because, let's face it, only a nutter would place themselves in danger for no reason.
In the case of the Voynich Manuscript, most people are happy to enjoy the frisson of danger that comes with the Refusal of the Call: a cipher manuscript is all too obviously a Macguffin, a siren call to a mad textual adventure that you simply wouldn't wish on anyone (let alone yourself). Anyone (such as myself) who has spent any significant time in the VMs' World Of Research Agony will readily verify that this is basically the case.
But I find it fascinating that the founding mythology of the 19th century Hermetic Order of the Golden Dawn was built around claimed cipher manuscripts. These had been owned by masonic scholar Kenneth Mackenzie, then found in a cupboard by Rev. A.F.A. Woodford in 1885, and then deciphered by William Wynn Westcott - the plaintext was in English, but had apparently been encrypted using a 15th century Trithemian-style cipher. Westcott then supposedly wrote to someone called Fraulein Anna Sprengel (whose contact details had helpfully been enciphered, though I can see no sign of them in the 56 released folios), who made him and his two collaborators "Exempt Adepts": and gave them a charter to work the five initiatory grades described in the cipher manuscripts.
Are the cipher manuscripts in any way genuine? Though the paper used for the 60 folios of the cipher was watermarked 1809, the association it mentions between the Tarot trumps and the Tree of Life was first proposed by Eliphas Levi only in 1855. And, for me, the simple act of using 45-year-old paper (never mind the constantly changing story surrounding the object, and the continued inability to find Anna Sprengel) makes me suspect that deception (or, at the very least, some kind of misleading myth-making) was intended right from the start.
Doubtless many of the hundreds of initiates who felt compelled by the unseen Gods to accept this Call to Adventure heartily enjoyed their foray into the Golden Dawn's DangerWorld. But regardless, the Cipher Manuscript at the heart of the constructed myth seems to have been nothing more than a Macguffin: Refusal of the Call is often exactly the right place to stop.