C. J. Mahaney is the senior pastor of Sovereign Grace Church of Louisville. He has written, edited and contributed to numerous books, including Proclaiming a Cross-Centered Theology; Don't Waste Your Sports; and Sex, Romance and the Glory of God. C. J. and his wife, Carolyn, are the parents of three married daughters and one son, and the happy grandparents to twelve grandchildren. John Piper (DTheol, University of Munich) is the founder and teacher of desiringGod.org and the chancellor of Bethlehem College & Seminary. He served for 33 years as the senior pastor of Bethlehem Baptist Church in Minneapolis, Minnesota, and is the author of more than 50 books, including Desiring God, Don't Waste Your Life, This Momentary Marriage, Bloodlines, and Does God Desire All to Be Saved? Dave Harvey (DMin, Westminster Theological Seminary) is the pastor of preaching at Four Oaks Community Church in Tallahassee, Florida. Dave has over 25 years of pastoral experience and has traveled nationally and internationally teaching Christians, equipping pastors, and training church planters. He is the Executive Director of Sojourn Network, founder of AmICalled.com, and serves on the board of the Christian Counseling and Educational Foundation (CCEF). Dave is the author of Am I Called?, Rescuing Ambition, and When Sinners Say I Do, as well as a contributing author to Worldliness: Resisting the Seduction of a Fallen World. Bob Kauflin is a pastor, songwriter, worship leader, and author with over thirty-five years experience. After pastoring for 12 years, he became director of Sovereign Grace Music in 1997. He oversees the production of their albums and teaches on congregational worship through WorshipGod conferences, seminars, and his blog, worshipmatters.com. He is currently an elder at Sovereign Grace Church in Louisville, Kentucky. He and his wife, Julie, have six children and an ever-growing number of grandchildren.