When I graduated with my doctoral degree in 1986, John Stott's magisterial book The Cross of Christ was published. This was great timing for me, since two of my areas of study were Christology and hermeneutical theories (theories of interpretation). And, the Atonement. The cross. Substitution (Christ, on the cross, took our place).
Oxford theologian Alister McGrath writes the Foreward to the 2021 special edition of Stott's book. He says,
"Since its publication in 1986, John Stott's The Cross of Christ has established itself as one of the most respected and authoritative evangelical reflections on this most important subject."
Stott's book "deals thoroughly with theories of the atonement..., examining its implications for Christian discipleship, the sacraments, and the enigmas of faith."
Stott writes: "The meaning of atonement is not to be found in our penitence evoked by the sight of Calvary, but rather in what God did when in Christ on the cross He took our place and bore our sin."
What did this accomplish? How important is this? Paul Eddy and James Beilby write: "Broadly speaking, the term atonement— one of the few theological terms that is “wholly and indigenously English”— refers to a reconciled state of “at-one-ness” between parties that were formerly alienated in some manner. According to the great eighteenth-century evangelist John Wesley, “Nothing in the Christian system is of greater consequence than the doctrine of the atonement.”"
(Schreiner, Thomas R.; Beilby, James; Eddy, Paul R.; Boyd, Gregory A.; Green, Joel B.; Reichenbach, Bruce. The Nature of the Atonement: Four Views (Spectrum Multiview Book Series) (p. 9)