Read carefully, widely, critically, and charitably.
A list of books (in no particular order) that have shaped my thinking and, I hope, will hence shape yours:
Mere Christianity by C. S. Lewis
My Utmost for His Highest by Oswald Chambers * (read it for free online)
A Severe Mercy by Sheldon Vanauken
The Great Divorce by C. S. Lewis
Orthodoxy by G. K. Chesterton
A Cry for Mercy by Henri Nouwen
What is the What by Dave Eggars
The Ragamuffin Gospel by Brennan Manning
Practicing the Presence of God by Brother Lawrence
Blue Like Jazz by Donald Miller
