Sanatan Dharam or Vedic Dharam is most ancient system and in existence since time immemorial, therefore called as Sanatan Dharam (the eternal faith). It is believed that Vedas are knowledge directly provided by God to ancient rishis. The commentaries on it are propounded by a large number rishis (Scientist) during over 5000 years. Hence, Hindu religion is not signified by one holy book and one prophet as in case of other religions world over but collection of knowledge gathered over thousands of years.
Essence of Hindu Religion
Hinduism consists of an extensive collection of ancient religious teachings on eternal truth based on Shruti (heard) and Smriti (memory). Shruti generally, include Vedas and Upnishads. Smriti include Upvedas, Purans, Vedangas (chanting of scriptures, grammar etc.), Ramayana, Mahabharata, Bhagwat Gita, Dharma Shastra (dharma of daily life, festivals, charity and pilgrimages and responsibilities of four ashrams), Darshana Shastra (six philosophical texts), Agama Shastra (practical aspects of devotion and worship) and Bhakti texts (of various poets & bhaktas).
Veda Vyasji in 3000 BC simplified and divided original one veda which are eternal into four viz. Rigveda, Samveda, Yajurveda and Atharvaveda. Vedas have five Up-vedas. Vedas deals into Karma kanda or rituals, Upasana Kanda or Worshipping and Jnana Kanda or knowledge. The Up-Vedas are the texts on the auxiliary themes of the Vedas. Archery, defence, war, politics and spiritual science (Dhanurveda), associated with the Rigveda. Architecture (Sthapatyaveda), associated with the Yajurveda. Music and sacred dance (Gāndharvaveda), associated with the Samaveda. Medicine (Āyurveda) & Social, Economic & Political (Arthveda), associated with the Atharvaveda.
Upnishads contain the essence or knowledge portion of vedas. About 251 Upnishads are found in texts but only 108 are available.
Purans are 18 and composed of four lakh shloks (Brahma, Padma, Vishnu, Shiva, Brahmand, Narad, Markaandeya, Agni, Bhavishyottara, Brahmavaivart, Ling, Varah, Skand, Vaman, Kurma, Matsya, Garud, Bhavatavatam).