Does anyone out there know any thing about telepasy.I now someone who is,but he !

Does anyone out there know any thing about telepasy.I now someone who is,but he will not explain it to me.?

Please explain how much a person can read your mind and how much.

You mean Telepathy, I think. As much as it is fiction, JK Rowling sums it up pretty well when Snape tells Harry the human mind is not like a book, to be opened and read.
A telepathist generally picks up the conscious and unconscious thought patterns, often what we're really thinking, despite saying something else. There are ways to block such people from picking up your thoughts. I'd recommend basic psychic self-defence if this concerns you. Imagine a sphere of white light surrounding you, like a shield of pure energy. That's a good start, but is very basic.