Rangaramanuja (17th century CE) was a commentator on Upanishads and several works of the Vishishtadvaita Vedanta School. He was a prolific writer belonging to the post-Vedanta Desika period. Rangaramanuja had his education under panchamabhanjana – Tatacharya and Vatsya Anantacharya. Mahacharya (Doddyaacharya) and Appayya Dikshita were his contemporaries. Of this 24 available works, 23 are in the form of commentaries and one is an independent work.
Bhava Prakashika of Rangaramanuja is a commentary on Sruta Prakasika the well known commentary on the Sri Bhashya of Ramanuja on Brahma Sutras of Badarayana. His Mula Bhava Prakashika is a direct commentary on Sri Bhashya. Nyatasiddhanjana-tika is a small commentary on Brahma Sutra, in the light of Vishishtadvaita Vedanta. A Sanskrit commentary called Bhagavad Vishaya on the Tamil composition Tiruvaymoli was also written by him.
An important contribution of Rangaramanuja is his commentary on the ten major Upanishads – Isha, Kena, Katha, Mundaka, Mandukya, Taittiriya, Aitareya, Prashna, Chandogya and Brihadaranyaka. He has also commented on certain minor Upanishads – Agni Rahasya, Athavashikha, Kaushitaki, Mantrika and Subala.
Ramanuja Acharya, the founder of Vishishtadvaita system, did not write any independent commentary on Upanishads; rather, he chose to explain certain knotty passages in them in his Vedartha Sangraha.
Rangaramanuja was the first to write independent commentaries on these Upanishads from the Visishtadvaita point of view. For this reason, he came to be known as Upanishad-bhashyakara. Another work of a similar nature by Rangaramanuja is Vishayavakyadipika, a commentary on the important Upanishadic passages quoted in Sri Bhashya.
The only independent work of Rangaramanuja is Siddhanta Sara, wherein he has set out the basic tenets of the Visishtadvaita School of Vedanta of Ramanuja.