Maitrayaniya Upanisad belongs to the Maitrayaniya Sakha of the Black Yajurveda. It appears to have originally formed a part of a lost Brahmana belnging to that Sakha, just as the Brhadaranyaka comes at the end of the Satapatha Brahmana. The preceding Karma kanda, acccording to the commentator, consisted to the commentator, consisted of four parts which described the various ceremonial rites; and the Upanisad was the fitting conclusion by which the initiated devotee is led from ceremonial to spiritual workship. Its main subject is a dialogue said to have been held between King Brhadratha and the saga Sakayanya, who relates the divine science of Brahman as it had been delivered to him by the sage Maitri or Maitreya, the son of Mitra.