Steve Jeffery is a minister at Emmanuel Evangelical Church in Southgate, London. He has a MS and PhD in experimental physics from Oxford University. Michael Ovey (1058-2017) was principal of Oak Hill Theological College for ten years. He received a PhD in Trinitarian theology from King's College, London. Andrew Sach is on the leadership team at St. Helen's Bishopsgate. He was previously a scientist before training at Oak Hill Theological College. 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.