Taittiriyaka-Vidya-Prakasah by Vidyaranya  

What Vidyaranya has accomplished in this independent work is best described as a 'meta-commentary', being not a mere gloss on the existing commentary, but an independent exercise in interpretation of the Upanisads themselves guided at every step by the turns in the commentary of Sankaracarya. The 'commentary' on the Taittiriyopanisad is entitled Taittiriyaka-vidya-prakasah, that is 'the exposition of the teaching of the Taittiriyopanisad'. It is to be seen that almost all Upanisads propound the unity of the Self with Brahman in two ways, firstly by negation and secondly by the mode of indicative descriptions. Both these methods are to be met with in the Taittiriyopanisad.