'How to Read a Book' by Mortimer J. Adler is claimed to be the most successful guide to reading comprehension. The majority of readers (myself included probably) exercise elementary reading. The book discusses higher forms of reading; inspectional, analytical and syntopic. It aims to teach readers different techniques for reading practical books, imaginative literature, plays, poetry, history, science, philosophy and mathematics.
True freedom is impossible without a mind made free by discipline; to read is a skill, therefore it is never passive. It requires certain mental effort. Reading skillfully means reading not just for amusement, but to get a meaningful understanding of something.
Extracting all you can from a book is invaluable advice for the dedicated reader. This quote sums it up perfectly:
"Good books are over your head; they would not be good for you if they were not. And books that are over your head weary you unless you can reach up to them and pull yourself up to their level. It is not the stretching that tires you, but the frustration of stretching unsuccessfully because you lack the skill to stretch effectively."