Have you thought about sharing this with the world Via museums? This is a fantastic treasure.
The OP Should sell it to the gates foundation, they like rare manuscripts
20M would be almost a record for a book if he sells it, but a couple have sold for more than 20M in history or rare books, the top sought after books for museums are guttenberg bible and the first folio and I don't think either one has ever gotten over 10M at public auction, but they're not that rare, quite a few exist of each one.
48 gb's exist
238 first folios exist
I think I read that 5 known 1568 copies the OP mentioned are known to exist in museums
There's a free tor file of the book written about this book, it's worth reading IMO and the way they explain stuff in the book, it is probably the only existing copy from 1566, since this is the only early Nostradamus work to have printer that printed a few other rare books in the 1550's, the 1568 editions have his son on it, so it looks like the original printer did this and that makes it 1566.
RARE and a TREASURE is an accurate description IMO and so is priceless but the OP says 20M buys it.
BILL GATES ARE YOU HERE?
Gates ponied up 30M for the only copy of Davinci's work, so 20M puts it in that range.
http://en.wikipedia.org/wiki/List_of_most_expensive_booksSo that's the level of that books and to see it on BCT is kind of shocking.
But it's here, it's tied to an ebay auction and the OP says it's in a bank vault only face to face.
INTERESTING post and a bonus for btc in how such an object can now use btc.
So 30M for the only davinic work, 20M for the only copy of the first edition of Nostradamus? Maybe to gates or a museum.
Will a bibliophile want it?
Probably, but outside of Gates and Museums who can sink 20M into a book.
haha