The _Vedânta sûtras_, also called Uttara Mîmâ@msâ, written by Bâdarâya@na, otherwise known as the _Brahma-sûtras_, form the original authoritative work of Vedânta. The word Vedânta means "end of the Veda," i.e. the Upani@sads, and the _Vedânta sûtras_ are so called as they are but a summarized statement of the general views of the Upani@sads. This work is divided into four books or adhyâyas and each adhyâya is divided into four pâdas or chapters. The first four sûtras of the work commonly known as _Catu@hsûtrî_ are (1) How to ask about Brahman, (2) From whom proceed birth and decay, (3) This is because from him the Vedas have come forth, (4) This is shown by the harmonious testimony of the Upani@sads. The whole of the first chapter of the second book is devoted to justifying the position of the Vedânta against the attacks of the rival schools. The second chapter of the second book is busy in dealing blows at rival systems. All the other parts of the book are devoted to settling the disputed interpretations of a number of individual Upani@sad texts. The really philosophical portion of the work is thus limited to the first four sûtras and the first and second chapters of the second book. The other portions are like commentaries to the Upani@sads, which however contain many theological views of the system. The first commentary of the _Brahma-sûtra_ was probably written by Baudhâyana, which however is not available now. The earliest commentary that is now found is that of the great S'a@nkara. His interpretations of the _Brahma-sûtras_ together with all the commentaries and other works that follow his views are popularly known as Vedânta philosophy, though this philosophy ought more properly to be called Vis'uddhâdvaitavâda school of Vedânta philosophy (i.e. the Vedânta philosophy of the school of absolute monism). Variant forms of dualistic philosophy as represented by the Vai@s@navas, S'aivas, Râmâyatas, etc., also claim to express the original purport of the Brahma sûtras. We thus find that apostles of dualistic creeds such as Râmânuja, Vallabha, Madhva, S'rîka@n@tha, Baladeva, etc., have written independent commentaries on the _Brahma-sûtra_ to show that the philosophy as elaborated by themselves is the view of the Upani@sads and as summarized in the _Brahma-sûtras_. These differed largely and often vehemently attacked S'a@nkara's interpretations of the same sûtras. These systems as expounded by them also pass by the name of Vedânta as these are also claimed to be the real interpretations intended by the Vedânta (Upani@sads) 71 and the _Vedânta sûtras_. Of these the system of Râmânuja has great philosophical importance.