This is a tale of faerie--of elves and changelings in the age of Vikings and dealing with creatures of Norse myth in the rhythms of the sagas. In this Foreward, Anderson writes of how elves had become a thing diminished in grandeur and stature:
In our day, J. R. R. Tolkien has restored the elves to something of what they formerly were, in his enchanting Ring cycle. However, he chose to make them not just beautiful and learned; they are wise grave, honorable, kindly embodiments of good will toward all things alive. In short, his elves belong more to the country of Gloriana than to that house in heathen Götaland.
Anderson harked back though to an even older tradition from the sagas of elves as powerful, yes--but also amoral and ruthless. And like those sagas this deals with powerful curses, magical implements, doomed love--no spoiler for this is stated early on with very heavy foreshadowing. It reminded me not so much of Tolkien as Wagner's Ring of the Niebelungenlied, based on similar material. This is very unlike Anderson's Three Hearts and Three Lions, written the year before the first version of this novel revised decades later. That story is entertaining and very light-hearted, this one is positively grim without a touch of humor. Yet I prefer this one a tad more. I suppose because there's something so timeless about this sort of story and this one cuts deeper into the heart.
