Leviathan by Scott Westerfeld
An alternate history steampunk novel. Very fun. The setting in WWI, but the Axis powers have walking war machines and the Allies have seriously genetically altered and weaponized animals (the book is named for a flying whale turned airship that's host to a whole ecological system). In this story the Austrian royalty whose assassinations started the whole war have a son who escapes with proof that he is indeed supposed to be the heir to the empire. I love speculative fiction--following all the rabbit trails of what-ifs and seeing just how far an author's imagination can take things. Fascinating. And an excellent read. It's the first of a trilogy, so I'm looking forward to tracking down the other books.