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 book one must read to learn natural sciences is the book of nature. The book from which to learn religion is your own mind and heart.
-Swami Vivekananda