Hindus did not know that they were Hindus until we told them so, nor that their land was called India. To them it was, and still is, Bharat, and has been so named since the time of the great emperor Bharat, whose life is recounted in their ancient histories. As for their religion, it did not have a name, any more than existence itself, because to live in Bharat meant to share a way of life common to all, a spiritual and material culture so all-pervading as to be invisible to those within it, like the air they breathed.
The word 'Hindu' entered the English language in the nineteenth century. It came from the Persians, whose Muslim descendants ruled India for close to a thousand years. They derived it from the river Indus, which flowed through the north western plains of the sub-continent and gave its name to the land and its people. How apt that in naming the religion of India, we should call it after its bio-region. Hindus, with their reverence for sacred rivers, mountains, forests and animals, have always been close to nature.
The two principle branches of Hinduism are Vaishnavism, which focuses on Vishnu and his avatars, and Shaivism, which follows Shiva. In essence these traditions are two sides of one coin. Although the information in this book is drawn from the Vaishnava tradition, most of it will be found to be common to both schools.
If Hinduism can be given a legitimate name it is 'Sanatan Dharma', which is used by many Hindus today. Roughly translated, this means 'the eternal essence of life'. This essence is not limited only to humans. It is the essential quality which unites all beings - human, animal or plant - with the universe that surrounds them and ultimately with the original source of their existence, the Godhead. This perception of underlying unity is what causes Hindus to steadfastly refuse to separate their religion from their daily life, or to separate their own faith from the other great faith traditions of the world. To them all religions are part of the process of discovering the unity of God, humanity and nature.