by Stephen Covey
This is not your ordinary self-help book. The author is very deliberate about avoiding quick-fixes and instead focuses on difficult truths and nuggets of wisdom that really make a difference. I have yet to find a better collection of wisdom than this book. I wish everyone on Earth would read it.
by David Allen
David lays out a metric ton of practical advice and mental models for getting organized. I don't do everything he suggests doing, but I've found it incredibly helpful to cherry-pick and adapt his suggestions to my own needs. This is a must-read for anyone who feel disorganized.
by Isaac Asimov
This is one of the classics of the Sci-fi genre. It predates Star Wars and Star Trek, so you'll definitely notice some of the themes those later works borrowed from Foundation. This series has a lot of interesting ideas about society at grand scales.
by Cixin Liu
Another highly popular Sci-fi series. It's probably one of the most mind-bending stories I've ever heard.
As a book of scripture, and as a companion to the Bible, this book contains lots of wonderful perspectives on things. I know this book has sparked a lot of controversy, but I urge you to at least take a look at it (even if you aren't religious), if not only so that you can say you've gone straight to the source instead of just hearing about it from other people.