Context, contemplation, careful study: things all but lost in the modern rush to shovel information into our eyeballs. Here's The Indy on slow reading, the antithesis of speed reading.
By default, most people read as quickly as they're comfortable with – this happens without any conscious effort. To start slow reading, you read as slowly as you're comfortable with – it should feel comfortable, not labored. The goal is to achieve an enjoyable experience – slow reading should never be stressful.
There's nothing new here, not even the term, found in Nietzsche ("perhaps one is a philologist still, that is to say, a teacher of slow reading") more than a hundred years ago. But the Slow movement is recent, dating to Roman irritation at the opening of a McDonalds there in the 1980s.