We've recently started a book-club at my current employer COMLINE. First of we talked about a book, that I've already reviewed here on the blog: "Pragmatic Unit Testing in Java 8 with JUnit".
In addition to simply refreshing my memory of the book something more interesting happened. Turns out that by not only reading the book but also considering how you'll discuss the book later, makes you read much more attentively and helps you remember better too. Usually when I read a novel late at night, I would sometimes be hard-pressed to remember even the previous chapter. But with a book-club you should at least remember until the next discussion.
One think I've learned from the excellent "Learning how to Learn" online course, is that you learn better if it's harder. This explains part of the difference to "casual" reading. Notes probably help a lot too, but the main difference surely is the attitude. When you read a book and build your mental model it's not the same if you're only reading for yourself or with an audience in mind. There's actually a book called "How to read a book", which describes this actually also teaches you how to read more "intelligently".
Since reading of any sort is an activity, all reading must to some degree be active. Completely passive reading is impossible; we cannot read with our eyes immobilized and our minds asleep. Hence when we contrast active with passive reading, our purpose is, first, to call attention to the fact that reading can be more or less active, and second, to point out that the more active the reading the better. One reader is better than another in proportion as he is capable of a greater range of activity in reading and exerts more effort. He is better if he demands more of himself and of the text before him.
This quote gives you an idea of their engaging style:
Why is marking a book indispensable to reading it? First, it keeps you awake -- not merely conscious, but wide awake.
This is one of the many motivating examples the authors give:
Reading is like skiing. When done well, when done by an expert, both reading and skiing are graceful, harmonious activities. When done by a beginner, both are awkward, frustrating, and slow.