The Upaniṣads — the philosophical core of the Vedic tradition, revealing the nature of Brahman, the Ātman, knowledge, action and liberation. The ten principal Upaniṣads together with select minor Vaiṣṇava Upaniṣads.
Twenty verses, opening with the riddle of the eight-legged swan — an image behind which stand the structure of the world and of a person. What follows is a brief exposition of Sāṅkhya's principles and the path by which the soul passes out of them to the unborn.