Character - Part Two

How is it that fictional characters made of words typed on paper become real in a reader's mind? How does that alchemy happen? I'm always surprised each time it happens for me - when I realize that I have fully accepted a character I'm reading, that I've made that little leap of faith that allows me not to question the artifice that is fiction but to surrender to the invention. I know that fiction is not "real", that the characters I'm reading don't exist. But they have become real for me...