Cardinal James Gibbons' famous and eloquent defense of Catholicism stands as one of the finest religious documents of his era, employing the Bible and devotional wisdom much more than arcane or complex theology. Writing in the 19th century, Cardinal Gibbons was moved to author this book after working for years in the priesthood. Seeking to remind readers of the vitality and merits of Catholicism, Gibbons attempts to both clarify the principles of the faith and spurn unjust criticisms. Religious concepts such as The Holy Trinity, and the important relationship the Bible has to the life of the church is investigated. The festivals and ritual sacraments that Catholics undertake, such as the taking of bread and wine to symbolize the flesh and the blood of Christ, are described in detail for their founding principles. Other traits of Catholicism, such as celibacy among the priesthood and the customs of matrimony, are explained.