On the surface of it, it sounds like and reads like a children's fantasy novel. But oh my, underneath, it's very deep indeed. I think it might be one that a person might read quite a few times and glean something different every time. Not as blatantly Christian as the Narnia books. In fact, in spite of all the talks of relics and angels and whatnot, I'm not so sure this is an allegory at all. I've not quite finished, but it is certainly holding my attention. So, yes, I'd recommend it to adult readers.I've always enjoyed reading about this particular medieval time period, and this does not disappoint, but don't look for historical accuracy, because it's not that kind of book. On the other hand, if you're not looking for politics, then how people who were different were treated is very accurate indeed.I have finished the book. It is rare that I am so impressed by a book that I immediately want to go out and purchase a copy for everyone I know. This is just such a book. To portray the co-existence of good and evil so beautifully takes the hand of a skilled author indeed. And I must backtrack my previous statement about historical accuracy. As I do my own research, I find the author's descriptions of that time period to be accurate. So, yes, READ THIS BOOK!!!