Every religion, including Christianity, in its original form is an inner religion, for there is only one truth, one gnosis. In thirteen chapters different aspects of the ancient and now ubiquitous concept of gnosis are discussed. Gnosis as knowledge of God, as love-wisdom, as profound insight into the true destiny of man as a microcosm, in short, gnosis as inner religion, is the theme of this fifth part in the crystal series. The reader receives insight into gnosis as a radiant activity, and its action on the soul principle present in every human being is explained to him. Texts appear in this volume of the Crystal series with the objective of bringing the seeking human being closer to the original purpose of being human.