Original Sin: Illuminating the Riddle is a short theological monograph based on Lectures given by Henri Blocher in 1995 at Moore Theological College in Sydney, Australia. It articulates the major contours of the Christian doctrine of original sin. D. A. Carson, a theologian from Trinity Evangelical Divinity School, writes that Blocher "is able to think through the interlocking contributions of historical theology, biblical theology and systematic theology, and come to fresh conclusions in the light of Scripture, without overturning all that is valuable from the past."