What Makes a Book Rare?

That question, among others, is posed to Dr. Bidwell of the Morgan Library.

From the article in the New York Times...

What makes a book rare: There are plenty of books that are valuable and not rare, and plenty of books that are rare and not valuable. Example: The Morgan is celebrated for being the one institution in the world for having three Gutenberg Bibles. You might say it’s not extremely rare because there are 50 known copies in various states of completeness in the world. On the other hand, we have plenty of early books that are the only known copy in the world, some of them deservedly so.

Why books become rare: Print media is supposed to make books common. It’s a mass production form of visual communication. So what went wrong to make that book so rare? Books may have been suppressed because of censorship, or books have gone out of fashion. So texts that we could consider very interesting now may have gone through a period of neglect that was nearly fatal.