Timothy James Keller (September 23, 1950 – May 19, 2023) was an American Presbyterian pastor, preacher, theologian, and Christian apologist. He was the chairman and co-founder of Redeemer City to City, which trains pastors for service around the world. Keller was also the founding pastor of Redeemer Presbyterian Church in New York City and the author of several The New York Times bestselling books, including 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 to the latter is Making Sense of GOD: An Invitation to the Skeptical (2016).