Los Upaniṣads — el núcleo filosófico de la tradición védica, que revela la naturaleza de Brahman, el Ātman, el conocimiento, la acción y la liberación. Los diez Upaniṣads principales junto con Upaniṣads vaiṣṇavas menores selectos.
Here two kinds of knowledge are distinguished for the first time: the lower — all the Vedas and sciences — and the higher, by which the Imperishable is known. Hence its famous images: two birds on one tree, the bow and arrow where the person himself becomes the arrow, and the warning about the "leaky boats" of rites.