Dating the veda
The "family books" (2–7) are so-called because they have hymns by members of the same clan in each book; but other clans are also represented in the Rigveda.In all, 10 families of rishis account for more than 95 per cent of the ṛcs; for each of them the Rigveda includes a lineage-specific āprī hymn (a special sūkta of rigidly formulaic structure, used for rituals.The most common numbering scheme is by book, hymn and stanza (and pada a, b, c ..., if required).E.g., the first verse is in three times eight syllables (gayatri): Most sūktas are attributed to single composers.
Some publishers give both classifications in a single edition.
The trishtubh meter (40%) and gayatri meter (25%) dominate in the Rigveda.
For pedagogical convenience, each mandala is divided into roughly equal sections of several sūktas, called anuvāka ("recitation"), which modern publishers often omit.
In the eight books that were composed the earliest, the hymns are mostly praise of specific deities..
The school-specific commentaries are known as Brahmanas (Aitareya-brahmana and Kaushitaki-brahmana) Aranyakas (Aitareya-aranyaka and Kaushitaki-aranyaka), and Upanishads (partly excerpted from the Aranyakas: Bahvrca-brahmana-upanishad, Aitareya-upanishad, Samhita-upanishad, Kaushitaki-upanishad).
The Padapatha and the Pratisakhya anchor the text's true meaning, In order to achieve this the oral tradition prescribed very structured enunciation, involving breaking down the Sanskrit compounds into stems and inflections, as well as certain permutations.