Constantine’s Sword is a sprawling work of history, theology, and personal confession by James Carroll (the author of An American Requiem, among many others). Carroll begins his landmark project by describing contemporary Catholic remembrances of the Holocaust and the Church’s intolerable legacy of hostility towards Jews. He then surveys Catholic anti-Judaism beginning with the New Testament and proceeding through the early Church, the Crusades, the Inquisition, the Enlightenment, and World War II, before concluding with “A Call for Vatican III,” a Church council that would make meaningful repentance for an entrenched tradition of hatred. Carroll’s prescriptions for repentance, continued in a powerful epilogue, are bracingly concrete: “there is no apology for Holy Week preaching that prompted pogroms until Holy Week liturgies, sermons, and readings have been purged of the anti-Jewish slanders that sent the mobs rushing out of church…. Forgiveness for the sin of anti-Semitism presumes a promise to dismantle all that makes it possible.” Carroll’s personal reflections as an American Catholic infuse his historical narrative, and although his reflections are sometimes unnecessarily detailed, they are admirable for the principle they express: “I find myself unable to accuse my Church of any sin that I cannot equally accuse myself of,” he writes. Carroll’s judgments on the Church are rightly harsh, even agonizing. And yet his vision for a future rapprochement between Christians and Jews is hopeful, in part because he personally has come to understand the deep connections between Israel and the Church: “Jesus offers me, a non-Jew, access to the biblical hope that was his birthright as a son of Israel.” —Michael Joseph Gross