The process changes slightly from role to role. Obviously, there are different things you're called on to do. You're not digging deep for Basher Tarr like I was for Paul Rusesabagina, but at the end of the day it's still all make-believe and you still are trying as realistically as you can to depict these characters.
The point really is that a writer tends to write a book that he or she tends to write. It's as simple as that. Of course, it's important to make a living and all that, but the main impulse as far as I'm concerned - and I'm sure as other writers are concerned - is to tell a story that I feel impelled by.