Wayne Grudem is research professor of Theology and Biblical Studies at Phoenix Seminary in Phoenix, Arizona. He holds degrees from Harvard (AB), Westminster Theological Seminary (MDiv, DD), and Cambridge (PhD). He is the author of more than a dozen books including the bestselling Systematic Theology.

Gregg Allison (PhD) is Professor of Christian Theology at The Southern Baptist Theological Seminary in Louisville, Kentucky where he teaches systematic theology.  Previously he served on Cru staff at the University of Notre Dame and overseas in Italy and the Italian-speaking region of Switzerland. He is a pastor of Sojourn Community Church, and is the theological strategist for Sojourn Network, a church planting network of about thirty churches. He is the author of Historical Theology: An Introduction to Christian Doctrine; Sojourners and Strangers: The Doctrine of the Church; and Roman Catholic Theology and Practice: An Evangelical Assessment.