The Chandogya Upanishad is one of the main ten Upanishads of Hinduism. It belongs to the Sama Veda. It is part of the Chandogya Brahmana which has ten chapters. The first two chapters of the Brahmana deal with sacrifices and other forms of worships. The other eight constitutes the Chandogya Upanishad. The Upanishad (उपनिषद्, Upaniá¹£ad) are part of the Hindu Shruti scriptures which primarily discuss meditation and philosophy and are seen as religious instructions by most schools of Hinduism. ... The Upanishads (उपनिषद्, Upanişad) are part of the Hindu Shruti scriptures which primarily discuss meditation and philosophy and are seen as religious instructions by most schools of Hinduism. ... Hinduism - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... The Sama Veda (सामवेद), or Veda of Holy Songs, is third in the usual order of enumeration of the four Vedas, the ancient core Hindu scriptures. ...

Though there are more than one hundred Upanishads, ten are principal. These are known as Dashopanishads and known for their philosophical depth and because Adi Shankara wrote commentaries on them. Adi Shankara (Śaṅkara, Shri Shankaracharya, Adhi Shankaracharya, Ādi Śaṅkarācārya; the first Shankara in his lineage), reverentially called Bhagavatpada Acharya (the teacher at the feet of Lord) (very approximately 788–820 C.E., but see below) was the most famous advaita philosopher, who had a profound influence...

Along with Brhdaranyaka Upanishad the Chandogyopanishad is an ancient source of principal fundamentals for Vedanta philosophy. Considering number of references made to this Upanishad in Brahma sutras indicates special importance of this Upanishad in Vedantic philosophy. Important spritual practices like Dahara vidya, Shandilya vidya, etc. are its speciality. Vedanta (Vedānta, वेदान्त, pronounced as ) is a principle branch of Hindu philosophy and is a form of Jnana Yoga (one of the four basic yoga practices in Hinduism; the others are: Raja Yoga, Bhakti Yoga, Karma Yoga), a form of yoga which involves an individual seeking the path of intellectual... Philosophy - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... The Brahma sutra is the nyaya prasthana, the logical text that sets forth the philosophy systematically (nyaya - logic/order). ...

Commentary

Of the available commentaries the oldest is the one written by Adi Shankara. Adi shankara has indicated that his commentary work is a brief book for those who want to know summary of this Upanishad. Commentator Ananda Giri has mentioned in his commentary that one Dramidacharya has written an elaborate and detailed commentary well before Adi Shakara. Very little is known about this Dramidacharya and his work is now lost. Adi Shankara (Śaṅkara, Shri Shankaracharya, Adhi Shankaracharya, Ādi Śaṅkarācārya; the first Shankara in his lineage), reverentially called Bhagavatpada Acharya (the teacher at the feet of Lord) (very approximately 788–820 C.E., but see below) was the most famous advaita philosopher, who had a profound influence... An acharya is a prominent guru, teacher and scholar who teaches by his own example (from Sanskrit achara, behavior). ...

Brahmanandi Tankacharya has written a brief explanation for this upanishad and Dramidacharya wrote an elaborate and detailed commentary on the work of Brahmanandi Tankacharya. Shri Ramanuja makes many references to these two scholars in his Vedanta Sangraha and Shree Bhashya both of which are commentary works. Sri Ramanuja Acharya (1017 - 1137 AD) was an Indian philosopher and is recognized as the most important saint of Sri Vaishnavism. ... There are several senses for Commentary: Informed criticism. ...

The first and the second chapters of this Upanishad discuss the problems of liturgy and doctrine such as the genesis and significance of Aum and the meaning and names of Saman. Aum (also Om, ॐ) is the most sacred syllable in Hinduism, first coming to light in the Vedic Tradition. ...

First chapter consists of eighteen subchapters in which the following are described:

1. Importance and greatness of universal holy syllable OM
2. Importance and greatness of Vital Life Force or Prana, and a story to explain the holiness of Prana describing how it remained untouched by evil while all other five senses got tainted by evil.
3. Fruits of meditating on holy syllable OM

The word Om and similar words have these meanings:- Aum, a sacred bijakshara (syllable) of Hinduism, Jainism and Sikhism; also relevant in Buddhism. ... In Hinduism, Prana is the infinite matter of which energy is born. ...

Sources

• S. Radhakrishnan, The Principal Upanishads
• Introduction by Sri Adidevananda: Chhandyogapanishads (Kannada translation)