The saying “Know Thyself” is a well-known hallmark of ancient philosophy. In Christianity this imperative assumes vital importance as a duty enjoined both by natural law and by Holy Scripture, for "they are wise who know themselves well" (Prov. 13:10). Since God created the human person according to His "image and likeness" (Gen. 1:26-27), self-knowledge is moreover a central path to attaining the knowledge of God. As Saint Gregory of Nyssa says, "If you wish to know God you must first know yourself." In this edifying book first published in Greek in 1905, Saint Nektarios gathers beneficial sayings and vividly portrays the various virtues, vices, and states of the soul. He aims to assist us in the difficult task of self-knowledge so that the reader can “study himself, examine himself with precision, behold the image of his soul as in a mirror so that he might discover its passions [...] and diligently seek his soul’s cure." Part One explores the virtues of faith, hope, and love, with descriptions of their beauty and meditations on their inestimable value.