Leviathan by Scott Westerfeld is sort of science fiction novel about WWI. It tells the story of Prince Aleksander who should have been the heir to the Austro-Hungarian empire and Deryn Sharp, a girl that disguises herself as a boy to get into the British Air Service. These two from very different backgrounds end up together on the huge British air ship the Leviathan. The British follow Darwin and make beasts to do things instead of machines. The Clanker countries make machines to do everything, and the two different ideals do not work well together, but are forced to as Alek and Deryn come to rely on each other and come to terms with their differences. This was interesting, and it took me a while to get what he was talking about with Darwinists and their "beasties" and the Clankers and their machines. Thankfully there are illustrations in each chapter so you can see what the machines and animals look like. I think boys would really like this book, and its sequel which I haven't read yet. Some fun summer reading.