Ramanuja (11th Century CE), also known as Ramanujacharya, was a theologian, philosopher, and scriptural exegete. He is seen by Sri Vaishnavas as the third and most important teacher (Acharya) of their tradition (after Nathamuni and Yamunacharya), and by Hindus in general as the leading expounder of Visishtadvaita, one of the classical interpretations of the dominant Vedanta school of Hindu philosophy.
Ramanuja may have written 9 books. They are also referred to as the nine precious gems, the Navarathnas.
1. His most famous work is known as the Sri Bhasya or Brahma Sutra Bhasya. It is a commentary on the Brahma Sutras.
2-4. Gadhya Thrayam (three prose hymns). All three are: Vaikunta Gadyam describing in great detail Vaikuntha, Sriranga Gadyam, a prayer of surrender to the feet of Ranganatha, Saranagati Gadyam, an imagined dialogue between Ramanuja and Shri (Lakshmi) and Narayana where he petitions Lakshmi to recommend Narayana to give him
5. Vedartha Sangraha (a resume of Vedanta). It sets out Ramanuja’s philosophy, which is theistic (it affirms a morally perfect, omniscient and omnipotent God) and
6. Vedanta Saara (essence of Vedanta) an appendix to Sri Bhasya
7. Vedanta Deepa (the light of Vedanta), another
8. Gita Bhashya ( his commentary on the Bhagavad Gita)
9. Nithya Grantham (About the day to day activities to be performed by all SriVaishnavas)