UPANIṢADS. The Upaniṣads are codified Sanskrit philosophical speculations of varying lengths in both prose and verse form, composed orally and set to memory mostly by anonymous South Asian sages, primarily in the classical and medieval periods. While the most important and influential Vedic Upaniṣads date from the eighth to the fourth centuries BCE, some lesser-known sectarian Upaniṣads appear as late as the sixteenth century CE. Individually and as a whole, the Upaniṣads present insights and doctrines that serve as the foundation for much of India's philosophical thought.

Traditional South Asian teachings based on the Upaniṣads have been called the Vedānta, the "end of the Veda," for the Upaniṣads chronologically and formally set the closure of the Vedic canon. Perhaps more to the point, Upaniṣadic lessons are said to be the end of the...