It's a great book if you ask me, by Neil Gaiman. The idea is that every deity that an immigrant has sacrified to in America has given them a place in the American phanteon. A young man, Shadow gets released from prison only to find that his wife just died in a car accident and that the mysterious Mr. Wednesday wants him to work for him. Oh, and that there is a war in heaven between the old gods and the new ones. And his dead wife isn't very good at staying put in her grave.

I don't know how well known Scandinavian mythology is known, but I don't think I spoil anything if I say that it was pretty easy for me to realise who Mr. Wednesday really was... And there are a number of other gods and other mythological creatures in a very long and rather slow book, which I kind of love. (Husband found it dead boring, though.)