It is possible. But with a large amount of time taken away for dedication. It's necromancy. And necromancy could be a nasty business. I prefer communicating or summoning spirits rather then try to physically or spiritually bring them fully back to this world. For all we know they could be lying and it could be a non human entity. Jesus was one of the only 'person' I heard about that actually raised a being physically from the dead and with no side-effects. There were powerful people like Merlin and so fort(of course it's if you believe in some of those things), necromancers, witches, mediums. All with great abilities but it could always get dangerous. So it's why the first thing you should ALWAYS do before attempting anything like this is protection. Either by religious prayers or your own spiritualism, you have to protect yourself.
For your question: Bringing things physically in their body back to life? I'm not sure. In what we do we encounter some crazy things in our own life so it wouldn't be that surprising. But if you think of it, even if you can bring someone to life you have to do it in about a year or months after they died. Doing it later there won't be anything to resurrect cause you'll only get bones. Summoning spirits however is very possible.
