Erasmus advised readers to learn quotations by heart and copy them everywhere: write them in the front and back of books; inscribe them on rings and cups; paint them on doors and walls, "even on the glass of a window." Emerson noted that "in Europe, every church is a kind of book or bible, so covered is it with inscriptions and pictures." In Arabic script as tall as a man, the Koran is quoted on the walls and domes of mosques. We quote to admire,...