SANATAN DHARMA, THE ETERNAL FAITH

Sanatan Dharam
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

• The Hindus found their creed upon the ancient Vedas, a word derived from Vid, "to know". They teach us the immortality of the soul.
• In Vedanta, Sat-Chit-Ananda (Existence-Knowledge-Bliss) is the highest concept of God possible to mind. It is essence of knowledge and is by its nature the essence of Bliss.
• Blessedness, eternal peace, arising from perfect freedom, is the highest concept of religion underlying all the ideas of God in Vedanta — absolutely free Existence, not bound by anything, no change, no nature, nothing that can produce a change in Him.
• God is self-evident, impersonal, omniscient, the Knower and Master of nature, the Lord of all. He is behind all worship and it is being done according to Him, whether we know it or not.
• Through lower forms of worship, man's material thoughts rise to spiritual worship and the Universal Infinite One is at last worshipped in and through the spirit.
• The Upanishads have declared, "Arise ! Awake ! and stop not until the goal is reached." We will then certainly cross the path, sharp as it is like the razor, and long and distant and difficult though it be. Man becomes the master of gods and demons. No one is to blame for our miseries but ourselves.

Hindu Scriptures
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).
 
References:

1. http://veda.wikidot.com/shad-darshana
2. Pantanjali yogpradeep by Shri Omanand Teerth, published by Gita press Gorakhpur.
3. https://en.wikipedia.org/wiki/