Centered on both the (fictional) son of Archiduke Ferdinand and a new recruit into the British Air-Service, Leviathan follows their exploits through the outbreak of an alternate World War I. In this world the 'clankers' (Germany etc) rely on diesel-powered weapons of war such as walking mech-type machines, and 'Darwinists' (Britian, France, etc) evolve their weapons and transportation from animals.

I expected to be more drawn in by the steampunkish (technically very little is actually steam-powered) side of the clankers, but the depictions of Darwinist fabrications were fascinating and grabbed me. Some of the these creatures are so outlandish that they'd be hard to picture in my head (whale-zeppelin, anyone?), but thankfully the book has some very nice illustrations.

Leviathan is the first of a trilogy, ending with a bit of a cliffhanger, but also resolves its own main story pretty well. Volume 2 is due out in October 2010, and I'll definitely be picking it up.

Leviathan is a quick, light read, but an extraordinarily fun one.