Review of Yank at Valhalla / Sun Destroyers

Well this is one of the better Ace Double books I've read and if I could give it a 7/10 then it would get that score. Both stories were written in the early 1940's and I have to say that The Sun Destroyers is an awesome story for the time. The characters in the book are the planets and stars and it's a very unique perspective. The other story, A Yank in Valhalla is pretty much your typical lost American in a strange distant past story. It's written well but I found the main character, Kieth, seems to accept his new surroundings way too quickly and even acts as if he's been fighting with the Norse Gods for a hundred years.