The System of the Vedanta according to Badarayana's Brahma-Sutras and Cankara's Commentary c5.s1.t2.2

c5.s1.t2.2

The great and not yet fully accessible complex of writings which bears the name of Veda, that is, "(theological) knowledge," and whose extent exceeds that of the Bible more than six times over, falls in the first place into four divisions, the Rigveda, Sâmaveda, Yajurveda and Atharvaveda; in each of these four Vedas we have to distinguish between three different classes of writings, according to content, form and age: 1) The Saṃhitâ, 2) The Brâhmaṇam, 3) The Sûtram; moreover the greater part of these twelve divisions exists in different, more or less divergent recensions, as used by the different schools for whose study they served, and these are commonly spoken of as the Çâkhâ's, that is, "the branches," of the Veda-tree. For an understanding of this complicated organism it will be useful to distinguish between the form in which the Veda exists at present, and the historical development through which it has grown to this form.