This is a great intellectual journey you are on. Keep reading! Two books I can immediately recommend are the non-fiction Meditations by Marcus Aurelius and the fictional novel Sophie's World by Jostein Gaarder. Free will, hmm, will I click submit on this comment.....

I'm not very well informed about these characters who allegedly walked the earth a couple thousand years ago, but... Do you think Jesus would have been corrupted if he were in Adam's shoes? Imagine Aristotle, Plato and Laozi stuck in a room together for a very long time - imagine the conversations that would take place. Aristotle and Plato would probably be chatting a lot - even arguing and asserting their egos. But given enough time, they will surely both see Laozi as their teacher.