This chapter introduces the Law of Unfoldment (jarthośtī daen), one of the foundational principles of Ilme Kṣnum, and presents it as the divinely ordained process through which the soul (urvān) returns from a state of material density toward its original condition of spiritual subtlety. Framed as a universal law of nature revealed by Zarathustra, the doctrine explains the mechanisms by which spiritual development unfolds through adherence to specific ethical, ritual, and bodily disciplines. The chapter outlines a complex body composition consisting of nine visible and invisible elements, situating human existence within a broader cosmological framework governed by subtle forces and invisible processes. Particular emphasis is placed on the concept of khoreh, understood as a form of personal spiritual radiance or subtle magnetism that mediates the soul’s progress through successive stages of refinement. The discussion further examines the ritual and practical measures required to preserve and strengthen khoreh, including dietary regulations, purity practices, the use of bull’s urine (nīraṃg), and the recitation of Avestan prayers. By integrating metaphysical speculation and ritual observance, the chapter exemplifies the Kṣnumic effort to interpret Zoroastrian tradition as a coherent science of spiritual evolution and cosmic order.