He was the author of "The New York Times" bestselling books "The Prodigal God: Recovering the Heart of the Christian Faith" (2008), "Prayer: Experiencing Awe and Intimacy with God" (2014), and "The Reason for God: Belief in an Age of Skepticism" (2008). The prequel for the latter is "Making Sense of GOD: An Invitation to the Skeptical" (2016).