About Hinduism
"Religion is one tree with many branches. As branches, you may say religions are many, but as tree, religion is only one"
Unlike most significant religions, Hinduism does not have a single founder or an event that started it. It has evolved since possibly around 3000 BC. It contains thousands of sects that all identify with Hinduism, but have different traditions, different deities or different names for the same deities. Hindu is the world's third largest religion, behind Christianity and Islam, with nearly 800 million followers. It originated from India but it gaining in popularity world-wide.
Most Hindus identify themselves as monotheistic (believing in one God) although Hinduism has many, many gods. This is because all the gods of Hinduism are various manifestations of one God. The three main manifestations (in some sects the only manifestations) are Brahma, the creator; Vishnu, the preserver; and Shiva, the Destroyer. As these three are one, so they have other personas as well.
A belief held by essentially all Hindus is reincarnation; being reborn after death to a new life. The quality of this new life is determined largely by the karma obtained in previous lives. Good and bad karma do not cancel each other out in Hinduism, but both are considered separately.
(Narayanan, Robinson)