The Upanishads (Sacred Books of the East, vols. 1 and 15)

This is Friedrich Max Muller's translation of the Upanishads, published in the Sacred Books of the East series through Clarendon Press, one of the first major systematic English translations of Sanskrit religious texts undertaken by a Western academic. Muller was a serious Sanskritist and his translation opened this material to English readers for the first time at real scale, which is a genuine and lasting contribution. Its limit is its age and the state of Sanskrit scholarship in the 1870s, later translators have revised some of Muller's readings, and his framing occasionally carries the comparative religion assumptions of his own Victorian academic context rather than the text's own. It is best read here as a foundational but dated translation, with specific difficult passages cross checked against a more modern rendering where precision matters.