Thinking Fast and Slow. This book discusses how we think and at what level and where some of the shortcuts we use when thinking occur and what impact they have on us. It really was one of the best books I've ever read; and like many books on that subject, you don't have to read the whole thing to get a lot out of it.
The Dictator's Handbook. This is the book that spawned the video essay series by CGP Gray: Rules of Rulers ( https://www.youtube.com/watch?v=rStL7niR7gs ). It has been a strong recommend for me on how and why the political world is the way it is.
Brain Lock: This is a book about OCD and it discusses a method of helping manage the symptoms and manifestations of OCD that creates a measurable and material change on the brain itself. Like self-help books, it does repeat itself quite a bit over the second half of the book. If you struggle with OCD, I do recommend it.