Who is Bill Denbrough from It and what is their importance?

When the novel begins, Bill Denbrough is a successful novelist in England for the filming of a movie version of one of his books. Bill's wife is a successful actress who is starring in this film. From the outside, Bill seems like a quiet, soft spoken man who has everything a person could possibly desire from life. However, a single phone call changes all of that. Bill takes a call from a childhood friend and suddenly memories begin coming back to him of a childhood that was less than perfect.