On the subject of reincarnation has a huge number of publications. Many efforts are made to understand this process. However, this phenomenon is inexplicable, as all that concerns the soul. But denying the phenomenon is impossible, since it accumulated a lot of amazing facts. There are cases recorded by specialists studying this phenomenon, which is not so easy to ignore.
In some religions it is believed that the soul can transmigrate only into the human body, while in others the transformation may be between sentient beings (people, angels, gods), and others imagine that in this cycle it is possible to include also animals, plants and even minerals!
Obviously, when an unhappy person dies, his next reincarnation is governed by the law of karma which prescribes the compensation to the victim and the punishment to the offender in the form caused them to have evil returned to him. Thus, the victim becomes a creature of a higher order, or blissful, and the one who offended him, — the poor or the vicious, bloodthirsty beast. So, the universal sense of justice is satisfied, and suffering no longer so hard.
Many of the examples of reincarnation, even when referring to documentary evidence, and I want to attribute to the imagination of authors of such messages. At the same time, declare all of fiction — difficult. There were too many for hundreds of years authoritative sages, philosophers and scientists who believed in reincarnation. And integrity of the majority of authors it is hard to doubt.