Greg Forster (PhD, Yale University) serves as the director of the Oikonomia Network at the Center for Transformational Churches at Trinity International University. He is a senior fellow at the Friedman Foundation for Educational Choice, the editor of the blog Hang Together, and a frequent conference speaker. TIMOTHY KELLER is founder and pastor of Redeemer Presbyterian Church in New York. He is the best-selling author of The Prodigal God and The Reason for God. Collin Hansen (MDiv, Trinity Evangelical Divinity School) serves as the editorial director for the Gospel Coalition. He previously worked as an associate editor for Christianity Today magazine and coedits the Cultural Renewal series with Tim Keller. He and his wife belong to Redeemer Community Church in Birmingham, Alabama, and he serves on the advisory board of Beeson Divinity School. You can follow him on Twitter at @collinhansen. TIMOTHY KELLER is founder and pastor of Redeemer Presbyterian Church in New York. He is the best-selling author of The Prodigal God and The Reason for God.