Written in 1712 by Saint Louis de Montfort, this influential Catholic treatise remained virtually unknown until it was discovered in France in 1842. Finally published in 1843 in its original French, the work became an instant success and would later have a profound impact on many Catholic popes. Pope John Paul II, a most devout believer in the importance of the Blessed Virgin Mary, said reading “True Devotion to Mary” was a “decisive turning point” in his life. Montfort believed that the easiest...