But if you wish to bring someone who has been dead for some time back from the dead, be very cautious. In order to gain, something of equal value must be lost. In resurrection, it means someone else must be dead in their place. If not, the subject will come back as something dark and unnatural. This is usually the start of zombies. This will be difficult for what could ever worth the same as a human soul than another human soul.
But in the opinion of most people, well in the words of that wizard philosopher:
"Give it up. It's never going to happen."