Who is Sheldon Vanauken from A Severe Mercy and what is their importance?

Sheldon Vanauken, or Van, is the protagonist and narrator of this story. He is a passionate student of literature and poetry, as well as sailing and music, and a lover of beauty in all its forms. He is a romantic and an intellectual who, at the beginning of the story, is a confirmed and happy pagan, thinking pleasurable and fair living with the acknowledgment that all that is must have been created by an intelligent being, or moral theism, the wisest course.