One of the major attributes of Hinduism is that it is an open religion, almost a way of life rather than a very disciplined formal institution. It emphasizies more on human and spiritual values than formal practices.
There is no founder, no distinct theological system, no ethical code (escept Manu Smriti), no centralized organization, no single holy book, nor a rigid code of laws in this religion. It emerges from the river valley civilisation as a continually evolving religious system, welcoming different strands of thoughts and beliefs.