Your source material is the people you know, not those you don't know, but every character is an extension of the author's own personality.
“You may observe in all my lessons, that I tell you how the legs go, and those who are unacquainted with that, are entirely ignorant and work in the dark.”
“I was never one to seek out the spotlight. I am kind of a private person, so I don't miss that part of show business at all.”