Protestants are baptized Christians but they do not enjoy full ecclesial communion with the Catholic Church. They generally follow the principal figures of the Protestant Reformation of the 16th century, foremost among them being Martin Luther. Three basic doctrines of Protestantism in general are Faith Alone (Sola Fide), Scripture Alone (Sola Scriptura) and Grace Alone (Sola Gratia). Faith Alone means that we are only saved by faith in Jesus Christ and not by any works whatsoever. Scripture Alone means that the Bible is the only infallible authority for Christian life and teaching. Grace Alone means that God “imputes” His righteousness to the Christian. The Catholic understanding of these matters is first, that we are saved and justified by faith in Jesus, but also by the good works which flow from that faith. Second, that the Church is an infallible authority as the interpreter of Sacred Scripture and witness to the Apostolic Tradition. Third, God’s saving grace is not simply imputed or loaned to the Christian, but rather it “transforms” the Christian. For almost a century, Protestants and Catholics have engaged with one another through various efforts to overcome these and other issues causing division, collectively known as “ecumenism.” In using the One Good Reason method with Protestants, evangelists should consider the personal histories of individuals and the corporate histories of their denominations in order to engage them effectively.