Ghosts really freak me out!  Do you believe in ghosts?
Why not? Ghosts are known as an apparition, phantom, shade, specter, spirit. They are thought to be the soul of a dead person or animal.
Have people throughout history always wonder if ghosts were real?
I am sure they have considered it. The attempt to contact the spirit of a deceased person is known as necromancy.
Necromancy is a creepy sounding word!  Is there any evidence to the validity of ghosts or spirits?
Depends who you ask. Necromancy is the practice of magic to communicate with the deceased, either by summoning their spirit or raising them bodily.