The primary scriptures of Hinduism, the Vedas (from the root vid, 'know') are revered as appaurusheya, 'not to human origin', and are honoured by epithets usually reserved for the gods, such as eternal, imperishable, infallible, indestructible.
Vedic litereature is generally divided into five periods: 1) Rig-vedic, named after certain hymns of the Rig-veda, written int eh earliest form of Vedic, most akin to Avestic; 2) Vedic of the Tenth Book of the Rig-veda, which is slightly later in date and form than the rest of the Rig-veda. Vedic from this period onwards is spoken of as Later Vedic; 3) to Brahmana period, largely prose, written in pedantic style with ritualistic purpose, indicative of the growing influence of caste; 4) the Aranyaka period, when the forest treatises, and the post-Brahmana philosophical Upanishads were composed; 5) the Sutra period (c. 500 BC to AD 100), written in verses characterized by gnomic style of great brevity. The sutras were the inspiration of a large literature later copied from this style. The Vedangas are sometimes included in this period.
There are four Vedas: Rigveda, Samaveda, Atharvaveda & Yajurveda.
Rigveda: Rigveda is the most important of the four Vedas. The Rigveda is a collection of miscellaneous fragments of old legends; chants and hymns, some of them of great beauty, put together comparatively late. Twenty one recensions of the Rigveda, representing the rituals of different schools and even different families, are known to tradition.
The Rigveda is divided into ten books called Mandala 'circles', or into eight parts called ashtaka, 'octaves' (or khanda 'trunks i.e. divisions). These boos are subdivided into adhyaya or chapters, and eight five anuvaka 'sections.
Mandala I is an ecletic ceremonial liturgy and veritable prayer book of the ancient priests. Mandala H to VII, the "Family Books", are credited to rishis of various important families such as Bhrigu, Vishvamitra, Angiras, Vasishtha, Atri, vamadeva. Book VI contains the poetry of the period before the tribes entered the Indian subcontinent.
Mandala VIII, a book of miscellaneous and supplementary hymns, mostly by members of the kanva family.
Mandala IX, a unique book in as much as it is almost exclusively devoted to a single deity, Soma.
Mandala X, differs from the other nine in subject and language. Many of the hymns are highly philosophical, some sacerdotal and legendary, others divinatory or designed for magical purposes and so on. There are prayers to the greater and lesser gods, to cows-rivers, dice and rain. The Purusha Sukta, which makes an allusion to the distinctions of caste, is found in this mandala.
Yajurveda: This is the second veda. The yajurveda is a priestly handbook, arranged in liturgical form for the performance of sacrifices (yaja), as its name implies. It embodies the sacrificial formulas in their entirety, prescribes rules for the construction of altars, for the new and full moon sacrifices.
The yajurveda now consists of two Samhitas, which once existed in one hundred and one recensions. But the samhitas contain almost the same subject matter but differently arranged. The Taittiriya Samhita, commonly called the Black Yajur-veda. The vajasneyi samhita or the white yajurveda was communicated to the sageyajnavalkya by the Sun-god in his equine form.
Samaveda: Samaveda is the third veda. The Samaveda embodies the knowledge of melodies and chants. The Samhita of this veda served as a text book for the priests who officiated at the soma sacrifices. It indicates the 'tunes' to which the sacred hymns are to be sung, by showing the prolongation, the repetition and interpolation of syllables required in the singing. The samaveda also contains a detailed account of the Soma rites. Many of the invocations in the samaveda are addressed to soma, some to Agni and some to Indra, jaiminiya shakha is the branch of Samaveda.
Atharvaveda: the fourth veda. The Atharvaveda embodies the magical formulary of ancient India, and much of it is devoted to spells, incantations, chants and charms. It is also referred to as the Brahmaveda because it served as the manual of the chief sacrificial priests, the Brahmins. A great deal is said in the Atharvaveda hymns about the Brahmins and the honours due to them.