The books are in every language—new books, ancient books, even a book on the history of Iraq that is seven hundred years old.

"His insight was that if you could get rid of the impurities, you could transmit light over many kilometers," says Jeff Scheck, who authored a history of fiber optics in 1999.

Those with mixed inclinations seek books capable of addressing several impulses at once: a literary novel with a twisty-turny plot, say, or a history of something like an oyster.