I just thought that would be a fun essay to read. It would discuss Ghost in the Shell, The Spirits Within, Paprika, maybe... what else do you think would be good?
I read a book about Ki (the Japanese symbol for breath and spirit) when I was trying to learn Kanji while living in Nagoya. Since my English reading material at the time was so limited, I have an almost supernatural memory for anything I read at the time.
Edit: I've just finished watching the anime series Mushishi. In these stories, the spirits are more like insects or fungus. They are a natural phenomenon that sometimes affect people when their lives intersect. I highly recommend it.