For strong readers who are Norse myth fans
For those with an interest in Norse mythology, this could be a lot of fun. For others, it may be just a bit too long and insufficiently engaging. To my taste, less would have been more in terms of using fewer of the Norse gods but developing their characters more -- as it is, there are lots of the gods but only a few get enough time to get much of a feel for their characters, and the rest just end up seeming like rather irritatingly quarrelsome flat figures. So while interesting, I didn't find the book fully satisfying. But there's where more familiarity with Norse mythology would probably aid in enjoyment. There's not much to be concerned about for ages 9 or 10 or so: the most bothersome aspect being the extensive visions of the torments of the dead in the underworld -- that does get pretty nasty. Other than that, the violence is not too much -- fairly typical for fantasy. And I hardly noticed the drinking or smoking the CSM reviewer mentions. So I'll say okay for ages 10+, though I think at the younger end of that range it would be only readers with particular interest who'd enjoy it.