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.
The important thing is how much less you think of the body, of yourself as matter -- as dead, dull, insentient matter; how much more you think of yourself as shining immortal being. The more you think of yourself as spirit, the more eager you will be to be absolutely free from matter, body and senses. This is the intense desire to be free.
-Swami Vivekananda