Deep reading — the kind that you engage in when you get lost in the syntax and imagery and the long, convoluted sentences of a really meaty book — is a special sort of exercise that creates a new part of the brain that did not exist at birth.

“It’s semi-miraculous, really,” said Dr. Wolf, the director of the Center for Reading and Language Research at Tufts University. “We don’t have genes for reading. It’s an activity we invented, and by doing it, we show that our brain has the capacity to go beyond itself, to take all these circuits that were created for oral language or vision, and do something entirely different with them — deduction, critical analysis, imagination, contemplation.”

There are three kinds of book owners. The first has all the standard sets and best-sellers—unread, untouched. (This deluded individual owns wood-pulp and ink, not books.) The second has a great many books—a few of them read through, most of them dipped into, but all of them as clean and shiny as the day they were bought. (This person would probably like to make books his own, but is restrained by a false respect for their physical appearance.) The third has a few books or many—every one of them dog-eared and dilapidated, shaken and loosened by continual use, marked and scribbled in from front to back. (This man owns books.)