Question: Does anyone know if an author can use someone's full name in their book without a formal release?

And if there was no formal release obtained, is that person entitled to any percentage of the profits?
[Edited 12/11/07 16:48pm]

Oh, I guess I should add I'm asking for the sake of my daughter, it's her name being used. I made a mistake once and I'm leary of repeating it again.

I'm gonna wite a novel with a main character named Imago, who is a dick.

Let's see him bring the litigation!

i think it depends on how the name was used, doesn't it?

if you use the name in an anecdote or if, say, you're referencing or critiquing a work that the person created, then i don't think a release needs to be signed.

if the book features an original interview or any kind of legitimate biographical profile, then maybe...?