Absolute One Holy Book

The Reality 

Hinduism does not revolves around a single book because it does not revolve around a single path to truth. The Bhagavad Gita is one of the most beloved and influential Hindu text, but it is only a part of much larger spiritual and philosophical tradition.

The Veds, Upanishads, Ramayan, Mahabharat, Purans, Agamas, ect. have guided different communities for centuries. 

At its core, Hindu thought holds that ultimate reality and truth are too vast to be confined to one scripture, one prophet or one interpretation.

The famous Vedic Idea :-

《Ekam Sat Vipra Bahudha Vadanti》

Means: "Truth is One, the wise describe it in many ways."

Rather than a religion of a single book, Hinduism is better understood as a civilization of many sacred texts, each offering a different perspective of Dharma,  Conciousness,  the Self and the Divine.