Share Christian non-fiction

There are some truly Godly Christian non-fiction authors out there. Do you have a favorite? One who writes passages and chapters that lodge in your heart and make you examine who you are and where you are on your Spiritual path?
On a postcard, tell your partner about one of your favorite non-fiction Christian authors. What have they written? Do you love everything they've written, or does one book stand out from the rest? Could this author become a favorite of your partner, too? Share your love of Christian authors! Any questions? Feel free to pm me!