Carl Bowen 
Thor and Loki [PDF ebook] 

Loki, the god of mischief, is Thor’s troublesome adopted brother. Their father Odin (ruler of the Viking gods), orders the quarrelsome siblings to tame the violent Giants once and for all together. But what Loki and Thor find in their series of adventures puts them in conflict with each other as well as with the giants. And in the land of Utgard, a mysterious place made from magic and illusion, Thor must trust his magic-wielding and misbehaving brother in order to get out alive. Likewise, Loki must count on his brother’s unmatched strength if he, too, hopes to survive their encounters with the Giants.