Brahmasutra consists of 555 sutras authored by Bhagawan Vedvyasa to logically remove any doubt on the oneness of Brahma and Atma mentioned in the Upanishads. The first 4 sutras are known as Chatursutri which are a comprehensive explanation of the Brahmasutra and generally studied if all sutras can not be studied. 

Swami Abhedananda has expansively opened each sutra in Chatursutri thereby giving an all encompassing view of Brahamsutra.