Leviathan

The first novel in a masterful trilogy about World War I with a steampunk twist by #1 New York Times bestselling author Scott Westerfeld.
It is the cusp of World War I. The Austro-Hungarians and Germans have their Clankers, steam-driven iron machines loaded with guns and ammunition. The British Darwinists employ genetically fabricated animals as their weaponry. Their Leviathan is a whale airship, and the most masterful beast in the British fleet.
Aleksandar Ferdinand, a Clanker, and Deryn Sharp, a Darwinist, are on opposite sides of the war. But their paths cross in the most unexpected way, taking them both aboard the Leviathan on a fantastical, around-the-world adventure…one that will change both their lives forever.