Books from The Great Books of the Western World that are available for free to download: If you’re not reading something technical for your job, read these classic books and make yourself a better person.
If you do want to read something technical for your job, let me suggest Think Complexity. It discusses graph algorithms, scale-free networks, fractals, and the game of life. It contains Python code, so it will also help you be a better programmer. I read most of it while awaiting assignment at Booz Allen.