The word Aranyakas means ‘the forest’ and these are called ‘forest books’ because they were written mainly for the hermits and students living in the jungles. These are the concluding portion of the Brahmanas or their appendices. They deal with philosophical doctrines and mysticism and not with rituals.
They lay emphasis not on sacrifices but on meditation. They are, in fact, opposed to sacrifices and many of the early rituals. Their stress is on moral values. They form a bridge between ‘Way of Work’ (Karma Marga) which was the sole concern of the Brahmanas and the ‘Way of Knowledge’ (Gyan Marga) which the Upanishads advocated.
The Aitareya Aranyaka is appended to the Aitareya Brahmana of the Rigveda. The Sankhyayana or Kaushitaki Aranyaka is the concluding portion of the Kaushitaki Brahmana of the Rigveda. In the Black Yajurveda, the Taittiriya Aranyaka is only a continuation of the Taittiriya Brahmana.
In the White Yajurveda, the 14th book of the Satapatha Brahmana is in name only an Aranyaka – the Brihdaranyaka. For the Samaveda, the only Aranyakas are the first Aranyaka-Wkt sections of the Chhandogya Upanishad, which belongs to the Tandyamaha Brahmana, and the Jaiminiya Upanishad Brahmana, which is nothing but an Aranyaka of the Jaiminiya or Talavakara school of the Samaveda and comprises the well known Kena (or Talvakara) Upanishad.