If you're looking for a book that will challenge you to go deep and really understand yourself, check out The Book of Secrets: Unlocking the Hidden Dimensions of Your Life by Deepak Chopra. This book made me think about the good, bad, and ugly… it wasn't always easy to read, but I benefited greatly from it. I really enjoy Deepak Chopra's insights from the spiritual and scientific perspectives... he blends these two perceived opposite forces to open us to new ways of thinking... very powerful stuff!