The Taittiriya-Upanisad is so called because of the recension (sakha) of the Krishna Yajurveda to which it is appended. It is the most popular and the best-known of all the Upanisads in this part of the country, where the majority of the Brahmins study the Taittiriya recension of the Yajurveda, and it is also one of the very few Upanisads which are still recited with the regulated accent and intonation which the solemnity of the subject therein treated naturally engenders. The Upanisad itself has been translated by several scholars including Prof. Max Muller; and the latest translation by Messrs. Mead and J.C. Chattopadhyaya, of the Blavatsky Lodge of the Theosophical Society, London, is the most 'soulful' of all, and at the same time the cheapest. A few words, therefore, are needed to explain the object of the present undertaking.Sankaracharya and Suresvaracharya are writers of highest authority belonging to what has been now-a days marked off as the Advaita school of the Vedanta. Every student of the Vedanta knows that the former has written commentaries on the classical Upanisads, on the Bhagavad-Gita, and on the Brahma sutras, besides a number of manuals and tracts treating of the Vedanta Philosophy, while among the works of the latter, which have but recently seen the light.