Man and His Symbols: Jung’s Entrance to the Unconscious. It was his last book so it holds a special place in my heart of one of the realist humans out there.
Depends on what you count as a philosophy book. As if you count Starship Troopers as one. Since it's basically Robert A. Heinlein's views and philosophy on culture and how the government should fuction and explaining why it should be. Sadly the movie was made by someone who hated it and try to change the story to make them "fascist" though the first movie, he was only the director and couldn't change the script. Though if you don't count that. I would say "Book of Five Rings"
This one. The introduction/forward is over half the book. Was not worth the time for me to read due to the length and potential for reframing the content afterward. The content from the original author was my intended read.
Note: Never say you haven't read something.
Attachments
The Praktikos & Chapters on Prayer (Monastic Studies) by Evagrius Ponticus; Translated by John...pdf