The Black Swan (anything by Taleb really), Meditations by Marcus Aurelius, Letters from a Stoic by Seneca, Epictetus' Discourses, Fish that ate the whale by Rich Cohen, Man's Search for Meaning, Titan, Principles by Ray Dalio (not really a book, but really worth reading, plus it's free), 4HW by Tim Ferris, The Strategy Paradox. Also Teddy Roosevelt's biography has been very influential.
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