Books, remember, used to be considered as compulsively all-consuming for young people as “Call of Duty 3’’ or binge-texting is now. Lovely Emma Bovary read too many romance novels and the next thing she knew she was cheating on her husband, running up huge debts, and putting fistfuls of arsenic in her mouth. Too many chivalric romances drove Don Quixote into psychosis, too: he read so many adventure novels he could no longer tell the difference between a belligerent giant and a windmill.