Although not well-known in the English-speaking world, Fr. Ambroise Gardeil, OP (1859-1931) was a Dominican of significant influence in French Catholic thought at the turn of the 20th century. Conservative theologians like Frs. Reginald Garrigou-Lagrange, OP, Michel Labourdette, OP, Jean-Hervé Nicolas, OP and many others hailed him as a careful expositor of the supernaturality of faith, a defender of the theological nature of rational apologetics, and a spiritual master. The True Christian Life provides a thorough and stirring introduction to Fr. Gardeil's work in spiritual theology. The volume was originally published posthumously through the collaboration of Fr. Gardeil's nephew, Fr. Henri-Dominique Gardeil, OP and Jacques Maritain. Fr. Ambroise, prior to beginning work on his masterpiece on spiritual experience, La Structure de l'âme et l'expérience mystique, drafted nearly eight-hundred pages that would have set forth a full presentation of moral-ascetical theology. While drafting this massive work, his reflection on the soul's receptive capacity for grace led him to the two-volume study, La Structure, and he never was able to finish his original designs for a comprehensive study of the Christian moral-spiritual life. Soon after his death, his nephew gathered several essays from the Revue thomiste and Revue de Jeunes, along with a complete-but-unpublished study on prayer. Drafting a lengthy introduction on the basis of Fr. Ambroise's unpublished notes, Fr. Henri-Dominique assembled a volume of moral / spiritual theology that sets out the principles of many important themes: divinization through grace, Christian prudence /conscience, the virtue of religion, devotion, and prayer. In this volume, the reader will find a clear and rhetorically striking presentation of the central mysteries of the spiritual life, presented with stirring and beautiful rhetoric by a theological master from the Thomist tradition.