"The Taittiriya Upanishad, a section of the Krishna or Black Yajur-Veda, forms the seventh, eighth, and ninth parts of the Taittiriya Aranyaka, which itself is a section of the Taittiriya Brahmana. The division of the Yajur-Veda into the White and Black recensions has been described elsewhere.
Though comparatively short, the Taittiriya Upanishad is one of the important Upanishads and is recited in many parts of India, even today, with proper accent and intonation. It is regarded as a source-book of the Vedanta philosophy. The topics discussed in it are arranged methodically, and the commentary written by Shankaracharya enhances its value. Shankaracharya has divided the Taittiriya Upanishad into three parts, called vallis."
- Swami Nikhilananda
"The Upanishad has been so named because it forms a part of the Taittiriya Aranyaka of the Krishna Yajur Veda, Taittiriya Aranyaka itself forms the latter part of the Taittiriya Branmana and this Upanishad constitutes the seventh, eighth and ninth prapathakas of the said Aranyaka.
The Taittiriya recension of the Krishna Yajur Veda got its nomenclature from the tradition that when the great sage Yajnavalkya was asked by his offended Guru to return back the Veda which the former had studied under him, Yajnavalkya threw it out, and other Rishis taking the forms of Tittiris (partridges) swallowed the Veda thus thrown out.
This Upanishad is the most popular of all other smaller Upanishads, chiefly owing to the fact that it is still chanted with proper swarams and intonations by Brahmins in all parts of India, which forms one of the main features of Hindu religious ceremonies. Moreover it speaks of the rules of conduct beginning from the student life up to the fourth Ashrama i.e., Sannyasa life, in well-ordered, graduated manner revealing the depth of significance of each stage and its final culmination into the next, till man reaches the summum bonum of life, the Brahmanandam.
It is divided into three parts, named according to Sankara, as (1) Shiksha-Valli, (2) Ananda-Valli, and (3) Bhrigu-Valli. But Sayana in his commentary on the Taittiriya Aranyaka styles them as (1) Samhiti, (2) Varuni and (3) Yagniki, according to the subject matters dealt therein."
- Swami Sharvananda
- A. Mahadeva Sastri - Taittiriya Upanishad
- S. Radhakrishnan - The Principal Upanishads
- S. Sitarama Sastri - The Upanishads - Volume V (with the commentary of Adi Shankaracharya)
- Swami Gambhirananda - Eight Upanishads - Volume I (with the commentary of Adi Shankaracharya)
- Swami Nikhilananda - The Upanishads - Volume IV (with the commentary of Adi Shankaracharya)
- Swami Paramarthananda - Taittiriya Upanishad (transcript of Swami Paramarthananda's classes)
- Swami Sharvananda - Taittiriya Upanishad
- Devanagari Script