Karma Nirnaya of Madhvacharya is a commentary on a part of Aitareya Brahmana of Vedic literature. Karma Nirnaya is an independent work, a monograph of Sri Madhvacharya. This is categorized as a prakarana grantha (ancillary work). It is an explanation of the philosophical meaning of the first chapter of the fourth division of Aitareya Brahmana, consisting of fourteen sections (suktas).
The benedictory verse gives a glimpse of the contents of the work. Madhvacharya offers his salutations to Vishnu, who is worshipped through the performance of yajna (sacrifice) by devas like Brahma, Rudra, and Indra and to whom the final offerings of the yajna are made.
This work helps those who perform yajnas but it also elaborates on the philosophical meanings of Rig Veda. The hymns are called mahanamni because the names Indra, Rudra etc., appearing there are not merely the names of devas but refer primarily to Vishnu. In fact, every word, every mantra, every sukta refers to Him only. The gods perform sacrifices and dedicate all to Him only.
Bhagavan Vishnu is called mahat since He possesses an infinite number of auspicious qualities. Some schools conceive of Him as nirguna simply means that He is free from influence of prakriti (i.e. sattva, rajas, tamas). Thus the nirguna passages do not contradict the saguna texts.
It is said that Vedic texts have several levels of meanings. In those, all Vedic words in their primary sense refer only to Vishnu. Other meanings come only after this. All rites and rituals should be performed with devotion to Vishnu and with detachment regarding worldly results. All sacrifices are to be offered at the feet of Vishnu. In the end, Madhvacharya dedicates his work to Narayana, who is dearest to him.