What are some good books on psychology and/or the human mind, and so on?
Just google "Jungian Psychology" or "Freudian Psychology". Some of the books are a mindfuck if you're not familiar with their phylosophical approach of writing. I don't know if they deliberately wrote them with such arrogance, but if you look past the pretentious words, they're a great read.
Quiet by Suzan Collins I believe it touches on introverts and extroverts. I found it fascinating.