Saint Alphonsus Liguori, the Prince of Moral Theologians, was one of the greatest preachers in Church history. A religious founder, consummate theologian, and holy man of God, St. Alphonsus never failed to utter a stirring word that drew out a lively penitence and redoubled dedication to the work of God from his audience. He was also a great mariologist and a devout son of Our Lady (his congregation eventually gained custody of the icon of Our Lady of Perpetual Help). In The Glories of Mary, he assembled the finest information on Our Lady from the many writings of the saints, holy authors, and Sacred Scripture. Included within these pages are the theological proofs for the Immaculate Conception, explanations of the invocations in the Litany of Loreto, and a description of Our Lady's death. The Glories of Mary is the greatest compendium of nearly eighteen centuries of teaching on Our Lady and seeks to lead many souls to a greater love of Jesus through a more intimate knowledge of Mary and her exalted role in our salvation. To this end, St. Alphonsus quotes many Fathers and Doctors of the Church, including Saint Bonaventure, who wrote, "No one can enter Heaven unless by Mary, as though through a door." Saint Alphonsus explains that Mary is the Gate of Heaven, the portal through which mankind meets the divine in Jesus Christ.

The Glories of Mary is five complete books in one volume. The first book examines the words of the Salve Regina and shows how God has given Mary to mankind as the Gate of Heaven. The second book explains Our Lady's principal feasts and reveals fresh truths about these mysteries. The third book explains the Seven Sorrows of Mary and why Our Lady's martyrdom was longer and greater than that of all other martyrs. The fourth book describes ten different virtues of Our Lady, and the fifth book provides dozens of famous prayers, meditations, and devotions to her.

"Out of the fullness of the heart, the mouth speaketh," and St. Alphonsu's heart was only filled to the brim with a genuine desire for innocence and purity of heart in all his spiritual children, most especially through devotion to the Blessed Mother. Writing to defend her against impious attacks and diminishments of Marian devotion, St. Alphonsus shows that devotion to Our Lady is a most certain mark of eternal salvation. His words give profound encouragement and firm hope for eternal victory through Mary, the Mother of God, who can obtain from her Divine Son anything she asks.