Different books for different ages: - Discourse on the Method [1], to become a healthy criticist of everything (perfect for your 15's-20's development) - Beyond Good and Evil [2], a definition of the 20th century craziness by the crazy genius Nietzsche (perfect for your 30's burnout) - The Praise of Folly [3], to realize that life is just a game (perfect for your 40's post-burnout rehab) - Propaganda [4], because you want to play the game too (perfect for your 50's meteoric rise to fame & success :). [1]: https://en.wikipedia.org/wiki/Discourse_on_the_Method [2]: https://en.wikipedia.org/wiki/Beyond_Good_and_Evil [3]: https://en.wikipedia.org/wiki/The_Praise_of_Folly [4]: https://en.wikipedia.org/wiki/Propaganda_%28book%29
Also recommended in this reply