Thanks to Jon Askonas and Matt Loftus for their help with this.
St. Augustine: Crazy Mixed-Up Love: How I Tried Everything Else And Accidentally Found Jesus
Martin Luther: Stop Going to Church: How the Church Undermines Authentic Christian Spirituality
John Calvin: When You Ask God Why: Systematic Answers to Unsystematic Questions
Desert Fathers: Byte Size Common Sense: Tweets from the Desert Fathers
Marcion: Searching for Scripture: Loving, Leaving, and Finding the Real Canon
Thomas Aquinas: The Dominican Guide to (Absolutely) Everything: Everyday Religion for Real Life
Jonathan Edwards: The Purpose-Driven Life: Discover the Secret of Why God Made the World
Boethius: A Cup of Comfort for the Christian Neoplatonist
St. Athanasius: ConSubstantial: What God Was Up To and How That Applies To You
John Henry Newman: Faking It: How I Finally Stopped Pretending To Be A Catholic And Actually Became One
…and then, six years later, his classic of religious epistemology:
John Henry Newman: Getting to Yes
Julian of Norwich: Endless Bliss: Sixteen Revelations to Revitalize Your Spirituality
Anselm: God-Man: Heavyweight Christianity for a Lightweight Church
Pope Paul VI: Real Sex: Everything You Wanted to Know About Sex But Assumed Was Forbidden
Benedict of Nursia: My Option: A Strategy for Living in a Post-Roman World