The Sacred Heart of Jesus, by noted nineteenth-century French prelate Mgr. Louis Gaston de Ségur, is a series of over thirty lessons and meditations designed to inspire the pious reader with a true and ardent devotion to the Sacred Heart. The book notably draws from Our Lord's revelations to St. Margaret Mary Alacoque and the writings of St. John Eudes. In the words of Mgr. de Ségur, "The purpose of this little work is to popularize the knowledge and therefore the love and worship of the Most Adorable and Most Sacred Heart of Our Lord Jesus Christ.... If I have the happiness of obtaining my goal, this little book can be of great service to those thousands of holy priests, zealous missionaries, fervent religious, and good and pious mothers of families seeking through all means to make truly known, served, and loved around them the God of their heart and the Heart of their God.... Our Lord having presented His Heart to be the refuge of souls in the trials of the last times, this work seems to me to enter His merciful designs." Included in the front of the book is an apostolic letter from His Holiness Pope Pius IX commending Mgr. de Ségur for his zeal in producing this edifying work.