Read fewer but better books. Deep reflection on fewer books is more valuable than consuming many books without thought.
Book: Essays and Aphorisms
From Philosopher Arthur Schopenhauer:
“As the biggest library if it is in disorder is not as useful as a small but well-arranged one, so you may accumulate a vast amount of knowledge but it will be of far less value to you than a much smaller amount if you have not thought it over for yourself; because only through ordering what you know by comparing every truth with every other truth can you take complete possession of your knowledge and get it into your power."
"You can think about only what you know, so you ought to learn something; on the other hand, you can know only what you have thought about."
Why? Because when we read, the author thinks for us. We can read ourselves stupid if we just repeat the author's mental process.