Small book. From inside cover : In this famous essay, late theologian J. I. Packer analyzes Scripture and the works of early Reformers to defend the truth of Christ's substitutionary suffering and death, the heart of the Christian gospel. Considered one of the most significant short works on penal substitutionary atonement from the twentieth century, this careful, concise essay has influenced prominent theologians and is essential reading for students, pastors, and laypeople alike.