Rig Veda - Knowledge of the Hymns of Praise.

It is divided into ten books (called mandalas) and has 1028 hymns in praise of various deities. The Rigveda is structured based on clear principles, these include Indra, Agni, Vishnu, Rudra, Varuna, and other early or “Vedic gods.” It also contains the famous Gayatri mantra and the prayer called the Purusha Shukta.
The Rig Veda was likely composed between roughly 1700–1100 BCE, making it one of the oldest texts and composed in Vedic Sanskrit, many of which are intended for various sacrificial rituals.

Sama Veda - Knowledge of the Melodies.

Sama Veda is divided into two sections, the earlier “black” and the more recent “white.
The first part includes four melody collections and the second part three verse. A melody in the song books corresponds to a verse in the arcika books.
Samaveda typically begin with hymns to Agni and Indra. In the Samaveda, some of the Rigvedic verses are repeated. Including repetitions, there are a total of 1875 verses numbered in the Samaveda recension translated by Griffith. Two major recensions have survived, the Kauthuma/Ranayaniya and the Jaiminiya.

The Yajur Veda - Knowledge of the Sacrificial formulas.

It is a compilation of ritual offering formulas that were said by a priest while an individual performed ritual actions such as those before the yajna fire, includes about 1,875 verses
There are two major groups of texts in this Veda: the Black (Krishna) and the White (Shukla).

Atharva Veda - Knowledge of the Magic formulas.

The Atharva veda has been a primary source for information about Vedic culture, the customs and beliefs, the aspirations and frustrations of everyday Vedic life.
The text also includes hymns dealing with the two major rituals of passage – marriage and cremation. The Atharva Veda also dedicates significant portion of the text asking the meaning of a ritual.