The Rigveda was included as a documentary heritage in the UNESCO Memory of the World Register in 2007. It is the earliest known scripture of the Hindus and also stands out as the first literary document in the history of humankind. This scripture has been preserved in the form of manuscripts in India. 
There are 30 manuscripts of the Rigveda at the Bhandarkar Institute. These were collected in the 19th century by Indologists such as Georg Bühler, and Franz Kielhorn from different parts of India, including Kashmir, Gujarat, and the then Rajputana, and the Central Provinces. The oldest manuscript dates back to 1464 A.D.  Out of the 30 manuscripts, one is written in the ancient Sharada script while the remaining 29 are written in the Devanagari script. These manuscripts have several unique features in terms of scripts, accentuation marks  and support material, which assist in a better reading of the text.
The Rigveda Samhita, which is the oldest section of the Rig Veda, is a collection of 1028 hymns dedicated to various deities who signify the forces of nature. Some of these deities are Indra (the god of war), Agni (the sacrificial fire), Soma (the sacred plant), and Usha (the Goddess of dawn). There is also Savitr, a solar deity, to whom the famous Gayatri Mantra is dedicated. The hymns were composed by Vedic sages who belonged to different clans, and include the famous rishis, Vishvamitra and Vasishtha. This is the reason why the hymns depict a great variation in style.

It is held that the Rigveda was first composed around 1500-1000 BCE. The hymns were preserved for a long time as an oral tradition. Thus they were memorized and verbally transmitted across generations for many centuries with utmost care. For this, a strict metrical scheme and a settled literary tradition were followed by the composers. It is believed that the Rigveda offers no direct evidence of the social or political life of the people in Vedic era, but an outline of culture does emerge through the hymns, the sacrificial instructions, and the philosophical musings found in this text. 

The significance of Rigveda lies in the fact that it is the oldest Indo-Aryan text and is unique and irreplaceable. The fact that it is available as a complete and intact text is a rare achievement, given its antiquity. Though archaic in origin, the text is not buried in the past and has not been forgotten over the centuries. It is an integral part of the living Hindu tradition. Vedic hymns are still recited at weddings and funerals and during the daily prayers, with the same subtleties of intonation and rhythm as the earlier times. This is not only true of India but also of all other countries in South and Southeast Asia, and parts of Central Asia, where Hinduism is being followed in the present times.