"Do you read a book a week?"

"If I spend more than an hour surfing on the internet, I find my thinking has changed, and with it, my concentration," says Nicholas Carr in The Shallows: What the Internet is Doing to Our Brains (2010). "The deep reading that used to come naturally has become a struggle." In July, Amazon announced that, for the first time, the sale of digital editions of books had overtaken the sale of hardbacks. But, Carr says, the…