Tim Keller is an American pastor, theologian, and author known for his influential work in the Christian community. He founded Redeemer Presbyterian Church in New York City in 1989, which grew to become a significant center for urban ministry. Keller is recognized for his ability to engage with contemporary culture and address complex spiritual questions. In addition to his pastoral work, Keller has written several books, including The Reason for God and The Prodigal God, which explore faith and doubt. He is also a co-founder of the Gospel Coalition, an organization that promotes gospel-centered ministry and resources for churches.