Timothy Keller (September 23, 1950–May 19, 2023) was a 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. He was also the founding pastor of Redeemer Presbyterian Church in New York City and 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). Keller earned his D.Min. from Westminster Theological Seminary and served on the faculty while doing urban ministry.