Of Vedas, Upanishads and Puranas!!

Was trying to answer to a question in a community forum and compiled this information up.

Mantras:
The Mantras are collected into anthologies called Samhitas. There are four Samhitas: the Rk (poetry), Saman (song), Yajus (prayer), and Atharvan (a kind of priest). They are commonly referred to as the Rig-Veda, Sama-Veda, Yajur-Veda, and Atharva-Veda respectively. The Rig-Veda contains the oldest part of the corpus, and consists of 1028 hymns. The Sama-Veda is mostly a rearrangement of the Rig-Veda for musical rendering. The Yajur-Veda gives sacrificial prayers and the Atharva-Veda gives charms, incantations and magical formulae. In addition to these there are some stray secular material, such as legends.
The next category of texts are the Brahmanas. These are ritual texts that describe in detail the sacrifices in which the Mantras were to be used, as well as comment on the meaning of the sacrificial ritual. Each of the Brahmanas is associated with one of the Samhitas. The Brahmanas may either form separate texts, or in the case of the Black Yajur Veda, can be partly integrated into the text of the Samhita. The most important of the Brahmanas is the Shatapatha Brahmana of the White Yajur Veda.

Upanishads:
The Aranyakas and Upanishads are theological and philosophical works. They are mystic or spiritual interpretations of the Vedas, and are considered their putative end and essence, and thus known as Vedanta ("the end of the Vedas"). They often form part of the Brahmanas (e.g. the Brhadaranyaka Upanishad).


Puranas:
Purana (meaning "ancient" or "old") is the name of a genre (or a group of related genres) of Indian written literature (as distinct from oral literature). Its general themes are history, tradition and religion. It is usually written in the form of stories related by one person to another.There are many texts designated as 'Purana.' The most important are:
Mahapuranas and Upapuranas - Written in Sanskrit. They usually adhere to the 'Panca-laksana' typology. They tell of the creation of the universe and the human race, narrate the genealogies of kings and saints, and contain assorted narratives, stories, and philosophical and religious topics.
Panca-laksana (Sanskrit 'five distinguishing marks'), are:
Sarga - The creation of the universe.
Pratisarga - Secondary creations, mostly re-creations after dissolution.
Vamsa - Genealogy of gods and sages.
Manvantara - The creation of the human race and the first human beings.
Vamsanucaritam - Dynastic histories

Additionally there are these too, but are believed to have evolved much later:

Sthala Puranas - Scriptures usually extolling the virtues of a certain Hindu temple. They narrate stories of the temple's creation and spiritual history.
Kula Puranas - Scriptures that deal with the origin and legends of a particular caste. The designation 'Purana' implicitly confers on a text a kind of factual aura, somewhat similar to the designation 'History' in Western discourse.

Classification of Puranas: Traditionally it is said that there are eighteen Mahapuranas and eighteen Upapuranas. Of the Mahapuranas it is said that six belong to the quality (guna) of goodness, six to passion, and six to ignorance

Origin: The Puranas are said to have been composed by the sage Vyasa, the narrator of the Mahabharata epic. Vyasa in Sanskrit means 'Divider,' and some scholars therefore take this simply as a term meaning 'Editor'. The texts, these scholars say, were probably written all over India and are being rewritten and reedited to the present day.
The Itihasa-Purana is mentioned in the Chandogya Upanishad.There are also references to the Puranas in the Atharvaveda, and the Satapatha Brahmana. There are probably also references to the Itihasa in the Nirukta.The Itihasa-Purana was considered to be almost as sacred and ancient as the Vedas, i.e. the "fifth Veda" according to the Brihad-aranyaka Upanishad.However, the ancient Itihasa-Purana was probably not exactly the same as the text of the Puranas that we know today. Scholars argue that some contents of the Puranas may date to an earlier period. According to Pargiter, the original Purana may date to the time of the final redaction of the Vedas.

How and why Srimad Bhagavatham was written by Veda Vyaasa

Vyaasa was not feeling happy – he felt as if he was lacking something. He had compiled the Vedas into four distinct Vedas of Rig Veda, Yajur Veda, Sama Veda and Atharva Veda – he also taught these to four of his disciples Paili, Vaishampaayana, Jaimini and Sumantu respectively. In order to make the reality apprehended by normal people who can’t grasp the truth of the Vedas directly, he compiled the 18 Puranas & 18 Upa Puranaas. He also wrote the Mahabharatham depicting the life of Kauravas and Pandavas along with Krishna’s life. But still he felt as if he was lacking something. He did not know the reason as to why he was feeling incomplete & hence sad.
At that time, Narada comes that way – Vyaasa then questions Narada about this. Narada then goes on to explain why Vyaasa was feeling incomplete & sad. Vyaasa had written Mahabharatham which propounded Dharma or righteousness. He did not give the ultimate reality the prime importance in Mahabharatham. This is very well known by people who know Mahabharatha which gives prime importance to Dharma alone. Thus, Narada says that whatever a person does forgetting the ultimate reality – it will lead only to sorrow & sufferings. Even if the work or action being done is a social service act or agnihotradi karma or propitiation of Lord Krishna. Any action which is done forgetting the ultimate reality of non-dual Consciousness will confer only sorrow & sufferings to the individual.For instance, When a person sees water in desert, if he forgets the reality of desert only being present – that moment, he runs behind water & since he doesn’t get it – he becomes sad. Similarly any action in the illusory world will give only sorrow unless it is associated with the thought of ultimate reality.This world which is an illusion is a big drama – the actor is not really the actor but he is the witness of the actions – he is the reality in which the illusory drama is seen. Remembering this reality, a person should do actions. Such actions lead to purification of mind & the person realizes his own eternal state of Existence, Consciousness and Bliss absolute.
Krishna says in GitaWhatever you do, whatever you eat, whatever offering you do, whatever daana you do, whatever austerity you do – offer it unto Me.- What is the effect of such offering???Thus, he becomes liberated from the bonds of likes & dislikes – and thereby gets liberated from the bondage of action – he thus becomes a detached person who is established in the reality & thus he attains Me (the ultimate reality of Brahman or Consciousness).
This is what Krishna again tells in Gita (this sloka below occurs in Vishnu Sahasranaama also)Ananyaaschintayanthomaam ye janaah pari upaasatheTeshaam nitya abhikyuktaanaam yoga kshemam vahaami aham
He who thinks about ME alone (as the ultimate reality) and worships me everywhere – he is always established in Me – I take of all his activities (good and bad both).A person when he is concentrating on the ultimate reality & without forgetting the ultimate reality does all actions – he thus gets established in the Self and realizes the eternal state of Bliss which is the natural state of every person. This is the ultimate aim of life.
Thus, Narada says to Vyaasa to expound the glory of the ultimate reality which alone is capable of conferring eternal bliss which is perfection & contentment. Thus Vyaasa wrote the Srimad Bhagavatham. Each and every chapter of Bhagavatham propounds this ultimate reality. There are instances where form of Vishnu or Krishna has been praised, Bhakthi and Karma have been praised – but in all those, we can find the ultimate reality being propounded. This is also the importance of Bhagavatham being able to confer the eternal bliss to the individual who undergoes a complete study of it.

Interesting, is'nt it?