"Expiation" is one of the most important concepts of the Christian faith, which unfortunately is hardly understood today: What does it mean that Jesus dies on the cross "as an expiation for our sins," as the New Testament emphasizes? What does John the Baptist mean when he calls Jesus - as impressively depicted on the Isenheim Altarpiece - "the Lamb of God" who "takes away the sin of the world"? Why do we celebrate in every holy mass that Christ's body was "given up for us" and Christ's blood was "poured out for the forgiveness of sins"? Father Karl Wallner invites us to seek the "meaning" of Christ's cross. He also wants to answer the question of why a mindset of "expiation," as practiced by many saints, is meaningful and redemptive for believing Christians.