Is knowledge of right and wrong written on the human heart? Do people know God from the world around them? Does natural knowledge contribute to Christian doctrine? While these questions of natural theology and natural law have historically been part of theological reflection, twentieth-century Protestant theologians’ radical reliance on revelation has eclipsed this historic connection. Stephen Grabill attempts the treacherous task of reintegration of Reformed Protestant theology with natural law by appealing to reformation era theologians such as John Calvin, Peter Martyr Vermigli, Johannes Althusius, and Francis Turretin who carried over and refined the traditional understanding of this key doctrine. In Rediscovering the Natural Law in Reformed Theological Ethics Stephen Grabill calls Christian ethicists, theologians and laypersons to take another look at this vital element in the history of Christian ethical thought.