1. A Praying Life by Paul Miller - Perhaps if you only read one more book on prayer in your entire life this should be it. It is probably the book that I read this year that I will remember the longest. It offered some of the best instruction on how prayer should be understood in the context of a whole life rather than just focusing on prayer as an aspect of spiritual life. It is theological, personal, and practical. As Miller opens up his life as a husband, father, parent of a child with a disability, and friend, the concepts he talks about come to life.
2. The Space Trilogy by C.S. Lewis - I hesitated for a long time to read this part of C.S. Lewis's work because it often gets very mixed reviews. I think it may be because some people simply do not engage well with science fiction. I came away from reading these works dumbfounded at C.S. Lewis's sheer ability to imagine and describe a story. I was also struck by how he is able to take theoretical ideas and instantiate them into a concrete situation. My guess is that if you want to be a good writer and teacher these two skills are indispensible
3. Surprised by Joy by C.S. Lewis - I read Lewis's autobiographical work about his early life and adult conversion to Christianity after reading The Space Trilogy. In reading it I found his early literary education inconceivable. It was intense, serious, and obviously powerful in effect. I feel like a late-comer to literature and language and cannot believe the type of education he received at such a young age. It helped me understand where some of the imagination came from.
4. The Prodigal God by Tim Keller - Keller's insight and application of the parable of the Prodigal Son deepened my love and affection for Christ and provided fresh perspective on understanding the variations of our human condition to use God for own ends. Our preference for using God rather than worshiping Him is subtly hidden and disguised as good. Seeing through the subtleties takes skill, experience, and a good grasp of the spiritual illness of sin. Keller displays all of these in this short but powerful book. If you are a Christian I would suggest you pick it up and read it, it will deepen your understanding of the core teaching of our faith. If you are not a Christian you should also take a shot at reading it and better understand our faith.