Listen, O Gautama, to the ancient and secret wisdom of Brahman, which I shall now reveal to you. I will explain how, at the moment of death, the journey of the self unfolds. Some embodied beings, according to their actions and understanding, enter wombs to be born again in physical bodies; others, shaped by their deeds and knowledge, become stationary forms, like plants. Yet, there is a being who, while others sleep, remains ever awake—creating desire after desire. He alone is the pure Self, the immortal Brahman, the foundation upon which all worlds rest. None can go beyond him—truly, this is that highest reality. Just as fire, though one, enters the world and takes the shape of every object it touches, so too does the inner Self, one and undivided, assume the forms of all beings, both within and without. As the wind, though single, moves everywhere and takes the shape of everything it enters, so does this inner Self dwell in all forms, manifesting in countless ways, inside and out. Consider the sun, the eye of the world: though it illuminates all, it is untouched by the impurities it reveals. In the same way, the inner Self of all beings remains pure, never tainted by the sorrows of the world, for it is beyond all suffering. He is the one ruler, the Self within all beings, who makes the one appear as many. The wise, who perceive him established in their own hearts, attain eternal happiness—none else do. He is the eternal among the transient, the conscious among the conscious, the one who fulfills the desires of the many. Those who realize him dwelling within themselves know everlasting peace—none else do. People ponder this supreme bliss, which is beyond description, wondering: “How may I know it? Does it shine, or does it not shine?” Know this: There, neither sun nor moon nor stars shine; not even lightning or fire can illumine it. That by whose light all else shines—by its radiance, this entire world is illumined. Picture the eternal aśvattha tree, with roots above and branches below. This tree is the very same pure immortal Brahman; upon him all worlds depend, and none surpass him—this indeed is that. All that exists here, this entire world, moves at the command of prāṇa, the vital force. It is a great and awesome presence, like a raised thunderbolt. Those who come to know this source of all become immortal. Out of awe for him, fire burns; from fear of him, the sun shines; Indra, Vāyu, and Death itself rush about their appointed tasks, compelled by his power. But if one fails to realize him here, before the body falls away, one becomes subject to further birth in the worlds of creation. The perception of the Self is different in each realm: as clear as a reflection in a mirror in the human world; as in a dream in the world of ancestors; as in water in the realm of gandharvas; as shadow and sunlight in the world of Brahman. One who understands the distinctness of the senses, their arising and setting, and their separate origins, becomes wise and does not grieve. Beyond the senses is the mind; beyond the mind is the higher intellect; beyond the intellect is the great Self; beyond the great Self is the unmanifest reality. Beyond even that is the all-pervading Person, without attributes. Knowing him, a living being is set free and attains immortality. His form cannot be seen with the eyes; none can behold him directly. He is grasped only by the heart, by thought, by the mind. Those who know him in this way become immortal. When the five senses, along with the mind, come to rest, and the intellect ceases to stir, that is called the highest state. This firm control of the senses is regarded as yoga. At that time, one must be especially vigilant, for yoga is the beginning and the end of all things. He cannot be attained by speech, nor by the mind, nor by the eye. Only by one who affirms, “He is,” can he be realized. He is to be realized as truly existing, in both aspects—manifest and unmanifest. For the one who sees him as real, his true nature becomes clear. When all desires that dwell in the heart are released, the mortal becomes immortal and attains Brahman here and now. When all the knots of the heart are broken here, the mortal becomes immortal—this alone is the supreme teaching. There are a hundred and one arteries of the heart; one of them rises to the crown of the head. By ascending through that, one attains immortality; the others, spreading in all directions, become the pathways of departure from this world. The inner Self, though no larger than a thumb, is ever seated in the hearts of all beings. With steadiness, draw him out from your own body, as one draws a reed from its sheath. Know him as pure, as immortal—know him, indeed, as pure and immortal. Having received this knowledge from Death himself, and the complete discipline of yoga, Nachiketas became united with Brahman, free from all stain, free from death. And so may anyone who comes to know the Self in this way. May that Self protect us both together; may he nourish us both together; may we strive together with great energy; may our study be vigorous and enlightening; may we never bear ill-will toward one another.