The Brahmana, described by Apastamba [आपस्तम्ब]( section of the Vedas containing precepts for sacrifice, reproof, praise, stories and traditions explain the connection between the Suktas[सुक्त] and the ceremonies ; they are treatises on ritual, but interspersed with the ritual directions, are many illustrative stories, philosophical observations and profound ideas, in certain Brahmanas [ब्राह्मण]. There are certain treatises or Books for the Forest, i. e., for study by recluses, are given at the end of the Brahmanas [ब्राह्मण]. There are also philosophical treatises of a profound character, embodying Brahmavidya [ब्रह्मविद्या], the science leading to enlightenment, on which the Six Darshanas [दर्शन], or the great systems of philosophy are built up.
They are many in number, 108 being the more important, and of these 10 or 12 are called Major, and the rest Minor. The Major have been commented on by the founders of the leading schools of Vedanta, or by their early disciples. The Samhita [सम्हिता], or Collections of the Mantras of the RigVeda contains over a 1000 Suktas, arranged in 108 Mandalas [मण्डल], literally circles. The Suktas are for the most part prayers to, and invocations of, the Devas, but we shall find later that the One Supreme Existence is also definitely taught in this ancient Aryan book. It is the book of the Hota [होतस], the priest who pours offerings into the fire, and, as its name implies, is the knowledge of Reechas [रीछस] or laudatory verses, to be recited aloud at the time of the sacrifice. The Samhita of the Yajurveda consists of forty Adhyayas [अध्याय], or chapters, containing over 1500 verses or shlokas [श्लोक], about half of which are also found in the Rigveda.
There are two main versions of it, the Krishna, the black, or Taittiriya [तैत्तिरीय], in which the Samhita and Brahmana are mixed up; and the Shukla, the white, or Vajasaneya [वाजसनेयि], in which the Samhita is separate from the Brahmana. There are other minor differences. The Samhita consists of the invocations and prayers offered in sacrifices in the preparation of the materials, the altar, the bricks, the stakes etc. Details of the sacrifices often mentioned in histories- the Rajasuya [राजसूय], the Ashvamedha [अश्वमेध], etc. may here be found as well as of domestic and other ceremonies. It is the book containing, as its name implies, the knowledge of sacrifices, and belongs especially to the Adhvaryuh [अध्वर्यु] (conductor), comprising his duties in a sacrifice. The Samhita of the Samaveda [सामवेद] contains 15 books divided into 32 chapters, again subdivided into 460 hymns. Most of these are also found in the RigVeda mantras, only 75 being different. The Samaveda is the knowledge of song, and its hymns were chanted by the experts of the mantras, at sacrifices in which Soma (special offerings [सोम]) was offered.
The Samhita of the Atharvaveda [अथर्ववेद] is divided into 20 Kandas [काण्ड], and these again into 731 hymns. Its earthly compilation is ascribed to the descendants of Atharvana [अथर्वण], the Angirasas [अंगिरस] and the Bhrigus [भृगु], to whom it was revealed. It is sometimes called Brahmaveda [ब्रह्मवेद], probably because it was the special Veda used by the Brahma, the chief priest at a sacrifice, who supervised the whole, and remedied any errors that might have been committed by the Hotri [होत्री], Adhvaryu [अध्वर्यु] and Udgatri [उद्गात्री]. The name, however, may refer to the fact that in the Atharvaveda is also expounded the knowledge of Brahman which bestows Moksha [मोक्ष], liberation from rebirth, many of the more famous Upanishads forming part of it. Further, it throws much light on the daily life of the ancient middle class Aryan, the merchant and the agriculturist as well as on that of the women of the same class, and thus had a special historical as well as sociological interest of its own.