important as well as the oldest—for it is the very foundation of all Vedic literature—is the Rigveda, the "Veda of verses" (from ṛich, "a laudatory stanza"), consisting entirely of lyrics, mainly in praise of different gods. It may, therefore, be described as the book of hymns or psalms. The Sāma-veda has practically no independent value, for it consists entirely of stanzas (excepting only 75) taken from the Rigveda and arranged solely with reference to their place in the Soma sacrifice. Being meant to be sung to certain fixed melodies, it may be called the book of chants (sāman). The Yajur-veda differs in one essential respect from the Sāma-veda. It consists not only of stanzas (ṛich), mostly borrowed from the Rigveda, but also of original prose formulas. It resembles the Sāma-veda, however, in having its contents arranged in the order in which it was actually employed in various sacrifices. It is, therefore, a book of sacrificial prayers (yajus). The matter of this Veda has been handed down in two forms. In the one, the sacrificial formulas only are given; in the other, these are to a certain extent intermingled with their explanations. These three Vedas alone were at first recognised as canonical scriptures, being in the next stage of Vedic literature comprehensively spoken of as "the threefold knowledge" (trayī vidyā).
The fourth collection, the Atharva-veda, attained to this position only after a long struggle. Judged both by its language and by that portion of its matter which is analogous to the contents of the Rigveda, the Atharva-veda came into existence considerably later than that Veda. In form it is similar to the Rigveda, consisting for the most part of metrical hymns, many of which are taken from the last book of the older collection. In