All the way, I felt I was reading this book while doing something else, and I only paid attention when it was especially interesting. There were interesting parts, some very nice sections in Wales, some very delightful conversations, beautiful imagery with the red dragon manifesting as an army. Really cool. But confusing. When did Hywl (this means Sail or Spunk in Welsh, by the way) lose one eye and get an magic English glass marble one? And why didn't he use it for anything other than watching that final battle? I certainly must have lost something in my inattentiveness...
...which could be a writing lesson, I think. Don't let your reader wander away. The writer is molding a story around them, determining what they will see and where they will go, like a magician with words when you think about it. (As of late, I have really been able to feel the sense of that, and it is propelling me into curiosity about semiotics, narratology, and in the inimitable words of Ira Glass, 'narrative control.')
Read more about John M. Ford.