I've always heard that it wa satanic. I guess they use it for calling up demons or something.
I would caution bout spending any time studying about it. It would be a waste of time. I was told by the Lord to not waste my time on anything of the sort for a couple reasons. That it is a distraction from keeping my focus on Jesus my Lord, and that it is not of the Kingdom of God and spending time on it even if I had all manner of good intentions about it, that it leaves a residue and will slowly draw one into it and further away from God.
He said that it is not important for His people to know these things. That much of it are lies and it is dangerous. And nothing that we need to know. And that if we need to know something, then He will tell us in due time. But meantime...Focus on Jesus and His Word and prayer & relationship.