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, A Peculiar Glory, and Reading the Bible Supernaturally. David Mathis serves as the executive editor at desiringGod.org, a pastor at Cities Church, and an adjunct professor at Bethlehem College & Seminary. His articles regularly appear at desiringGod.org/mathis. David and his wife, Megan, have three children. Kevin DeYoung (MDiv, Gordon-Conwell Theological Seminary) is the senior pastor at Christ Covenant Church in Matthews, North Carolina. He serves as a council member at the Gospel Coalition and blogs at DeYoung, Restless, and Reformed. He is assistant professor of systematic theology at Reformed Theological Seminary (Charlotte) and a PhD candidate at the University of Leicester. He is the author of several books, including Just Do Something, Crazy Busy, and The Biggest Story. Kevin and his wife, Trisha, have seven children. Russell Moore (PhD, The Southern Baptist Theological Seminary) is the eighth president of the Ethics & Religious Liberty Commission of the Southern Baptist Convention, the moral and public policy agency of the nation's largest Protestant denomination. A widely-sought commentator, Dr. Moore has been called "vigorous, cheerful, and fiercely articulate" by the Wall Street Journal. He is the author of several books, including Onward, The Kingdom of Christ, Adopted for Life, and Tempted and Tried, and he blogs regularly at RussellMoore.com and tweets at @drmoore. He and his wife, Maria, have five sons. Edward T. Welch (PhD, University of Utah) is a counselor and faculty member at the Christian Counseling & Educational Foundation. He has been counseling for more than 35 years and has written extensively on the topics of depression, fear, and addictions. His books include When People Are Big and God Is Small, Crossroads: A Step-by-Step Guide Away From Addiction, Running Scared: Fear, Worry and the God of Rest, Shame Interrupted, and Side by Side. He blogs regularly at CCEF.org.