“The writer Umberto Eco belongs to that small class of scholars who are encyclopedic, insightful, and non dull. He is the owner of a large personal library (containing thirty thousand books), and separates visitors into two categories: those who react with 'Wow! Signore professore dottore Eco, what a library you have! How many of these books have you read?' and the others - a very small minority - who get the point that a private library is not an ego-boosting appendage but a research tool. Read books are far less valuable than unread ones. The library should contain as much of what you do not know as your financial means, mortgage rates, and the currently tight read-estate market allows you to put there. You will accumulate more knowledge and more books as you grow older, and the growing number of unread books on the shelves will look at you menacingly. Indeed, the more you know, the larger the rows of unread books. Let us call this collection of unread books an antilibrary.”
See also Umberto Eco's Anti-Library, c/o Taleb:
From the kitchen, without much interest: "No idea."
"They'd always ask it with the kind of voice people use in the presence of large sculptures in museums. They'd ask me, 'Have you read all these books?'" He waited again, but Billy Kinetta was not playing the game. "Well, young fella, after a while the same dumb question gets asked a million times, you get sorta snappish about it. And it came to annoy me more than a little bit. Till I finally figured out the right answer.
"And you know what that answer was? Go ahead, take a guess." Billy appeared in the kitchenette doorway.
"I suppose you told them you'd read a lot of them but not all of them."
Gaspar waved the guess away with a flapping hand. "Now what good would that have done? They wouldn't know they'd asked a dumb question, but I didn't want to insult them, either. So when they'd ask if I'd read all those books, I'd say, 'Hell, no. Who wants a library full of books you've already read?'"
http://harlanellison.com/iwrite/paladin.htm