Hinduism is not a normal religion like we are use to, the Hinduism is a myraid of many different religious ideologies and practices that were eventually blended into one religion known as 'Hinduism' by the British. The Indians followed and their eventually their decendants continued. The regional differences which spawn sub-cultural differences also spawn the different streams of religious practice that make up Hinduism.
In the religion of Hinduism, they believe in repetitious Transmigration of the soul. What this means to me is the transfer of one’s soul after death into another body which is born; this sounds somewhat what we call rebirth. This ensures that one will die and be rebirth over and over, a continuing cycle or birth, life and death and rebirth though they are many lifetimes. How interesting is that, what one could not accomplish in one lifetime he or she can be born again and finish, This would ultimately change the world, if this happens to someone that may have the cure for cancer or something, and that person has not completed the mission, they have almost eternity to do so. I guess that this does not happen or we just do not know that we have that power and are capable of doing such things or we would be a perfect world. This Transmigration of the soul is often called Samsara. Karma is the accumulated sum of the ones good and bad deeds. Karma determines how you will live your next life. Therefore, if you are almost at the point where you can find a cure to an incurable disease, you may be rebirth and if you are an evil person, you most likely will not be rebirth. Through pure acts, thought and devotion one can be reborn at a higher level.