Reading is an activity, and all activity involves an active reception of the world. The more active the reading, the better. The reader who is more active will get more out of his reading than the one who is passive.
There is a sense, however, in which reading is necessarily passive. We cannot read without taking in the words on the page; the author has done his work, and we receive it. But to understand is to do more than receive — it is to grasp, to question, to come to terms.
The art of reading, in short, includes all of the same skills that are involved in the art of unaided discovery: keenness of observation, readily available memory, range of imagination, and an intellect trained in analysis and reflection.
When we read for understanding, we are reaching up from a state of understanding less to one of understanding more. The writer must be superior to the reader in understanding, and his book must convey in readable form the insights he possesses and his potential readers lack.