Infallability is a deeply misunderstood idea, within as well as outside the Catholic Church. It remains a subject of great theological debate, especially regarding papal infallibility and the ordinary magisterium of the Church. In The Gift of Infallibility, theologian James T. O'Connor clarifies the idea of infallibility. He provides a helpful translation of the "relatio" or official explanation by Bishop Gasser given at Vatican I, the Church council that defined the dogma of papal infallibility. Also included in this important volume is the first draft of chapter 4 of the dogmatic constitution Pastor Aeternus, as well as the final, official chapter of the constitution. The volume concludes with a recently updated theological summary on the topic of infallibility by Father O'Connor. The Gift of Infallibility is immensely important for theologians and others who wish to understand the way by which the Holy Spirit safeguards the Church from error.