Quote from Essays and Aphorisms by 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 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.

Schopenhauer’s recipe for useful knowledge:

• some information
• lots of critical thinking
• well organized

References:

Nick Wignall page on Schopenhauer