Tony Reinke is a nonprofit journalist and serves as senior teacher and host of the Ask Pastor John podcast for desiringGod.org. He is the author of Lit!: A Christian Guide to Reading Books; 12 Ways Your Phone Is Changing You; and God, Technology, and the Christian Life.  Stephen J. Nichols (PhD, Westminster Theological Seminary) serves as the president of Reformation Bible College and chief academic officer of Ligonier Ministries. He has written over twenty books and is an editor of the Theologians on the Christian Life series. He also hosts the weekly podcast 5 Minutes in Church History. Justin Taylor (PhD, The Southern Baptist Theological Seminary) is the executive vice president of book publishing and book publisher at Crossway. He has edited and contributed to several books, and he blogs at Between Two Worlds—hosted by the Gospel Coalition. John Piper is founder and lead teacher of desiringGod.org and chancellor of Bethlehem College & Seminary. He served for thirty-three years as a pastor at Bethlehem Baptist Church in Minneapolis, Minnesota, and is the author of more than fifty books, including Desiring God; Don’t Waste Your Life; and Providence.