This book depicts the human experience of spirituality by examining the nature of the soul, path to salvation, and strategies for strengthening one's union with God. Father Adolphe Tanquerey sources his inspirational guidance from Sacred Scripture in addition to the writings of spiritual leaders and saints, including Thomas Aquinas. In this pioneering and instructional work, Father Tanquerey has compiled a complete, practical, and orderly overview of all the questions concerning the spiritual life in one volume. Although initially intended for clergy, this text proves especially efficacious in showing faithful followers the path to piety.