Whoa. Wait. What?

Tell me if something in this headline catches your eye like it did mine:

Christie's to Sell Previously Unknown Copy of Shakespeare's First Folio

What the heck is a "previously unknown" folio? You don't just drop something like that into a headline and walk away.  Everybody knows that all the "known" Folios (233) are accounted for and micro-catalogued, and if Christie's had one in its collection, surely it would not be a secret, would it? Surely this is some fancy word wrangling for publicity, like everybody calling Sir Thomas More "Shakespeare's Last Play" and "The Only Play Written in Shakespeare's Handwriting."

"...and the volume for sale at Christie's is a new addition to that list."

Interesting!  Tell me more. How can this be?

Christie's estimates the previously unrecorded copy currently for sale will fetch £800,000–1.2 million (about $1.16 million–1.74 million). It has not been seen by the public in over two centuries, and last changed hands in 1800, when it was purchased by book collector George Augustus Shuckburgh-Evelyn (1751–1804).

 I'm having trouble getting my head around this.  You mean to tell me that the people who run this sort of thing have had one of the most rare and valuable books in the world in its collection, potentially for centuries, and not only did they not let anybody see it, THEY DIDN'T EVEN TELL ANYBODY IT EXISTED??

What's next up for auction, all of Shakespeare's personal library, Amelia Earhart's skeleton and the Holy Grail?