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.
I am the thread that runs through all these pearls, and each pearl is a religion or even a sect thereof. Such are the different pearls, and God is the thread that runs through all of them; most people, however, are entirely unconscious of it.
-Swami Vivekananda