And it demands more than our eyes. The most physically active we may get while reading a book is to flip the pages or dog-ear a corner. But screens engage our bodies. Touch screens respond to the ceaseless caress of our fingers. Sensors in game consoles such as the Nintendo Wii track our hands and arms. We interact with what we see. Soon enough, screens will follow our eyes to perceive where we gaze. A screen will know what we are paying attention to and for how long. In the futuristic movie Minority Report (2002), the character played by Tom Cruise stands in front of a wraparound screen and hunts through vast archives of information with the gestures of a symphony conductor. Reading becomes almost athletic. Just as it seemed weird five centuries ago to see someone read silently, in the future it will seem weird to read without moving your body.
