Brahma Sutras systematizes the philosophy of the Upanishads in 555 aphorisms. In this book the original aphorisms are given in Devanagari followed by word-for-word English rendering, and the interpretation of the sutra according to Shankaracharya. The introduction contains a comparative study of the bhashyas of Shankara, Ramanuja, and Nimbarka.
As soon as I think that I am a little body, I want to preserve it, to protect it, to keep it nice, at the expense of other bodies; then you and I become separate.
-Swami Vivekananda