What is the theme in The Writing Life by Annie Dillard?

Throughout the book, the author portrays the process of writing in two different ways that, at first, seem contradictory but are in fact complimentary. The first is made apparent in the very first chapter, in which she describes the hard work, at times torturous work, of shaping a piece of writing so that it effectively evokes the "line of words" that she suggests is the core identity of a piece of writing. She goes to considerable lengths to describe how the path of that line cannot, or should not, be allowed to diverge from its destination of truth, and how the writer cannot, or should not, allow him or herself to be distracted from that destination by favorite pieces of writing, habits, or old perspectives.