The one book outside of Scripture that has most profoundly impacted me is A.W. Tozer’s Knowledge of the Holy. He begins his work with this:
What comes into our minds when we think about God is the most important thing about us.
Tozer’s right. In Proverbs, we see—again and again—an emphasis on the fear of the Lord. It’s the beginning of wisdom (9:10), our source of strong confidence (14:26), and our fountain of life (14:27). Each of these begin with a proper view of God that results in a fear of the Lord.